diff options
author | Kevin Hilman <khilman@linaro.org> | 2015-12-08 16:03:46 -0800 |
---|---|---|
committer | Kevin Hilman <khilman@linaro.org> | 2015-12-08 16:03:46 -0800 |
commit | abacc500b7cddb62f7efc04d7c21d56375f42646 (patch) | |
tree | 66f38c531bfce494b836d9c9227fe208dd79e955 | |
parent | e46761bb82818df3c422f784cc8fba9b40fd0ad6 (diff) | |
parent | 20af540051e1c1f7a7d9b9e4613c1ecc53ded4a6 (diff) |
Merge branch 'pan-3.18' of https://git.linaro.org/people/david.brown/linux-lsk into linux-linaro-lsk-v3.18
* 'pan-3.18' of https://git.linaro.org/people/david.brown/linux-lsk: (27 commits)
arm64: kernel: Add support for Privileged Access Never
arm64: Generalise msr_s/mrs_s operations
arm64: kernel: Add cpufeature 'enable' callback
arm64: kernel: Add cpuid_feature_extract_field() for 4bit sign extension
arm64: kernel: Add min_field_value and use '>=' for feature detection
arm64: kernel: Add optional CONFIG_ parameter to ALTERNATIVE()
arm64: alternative: Provide if/else/endif assembler macros
arm64: alternative: Work around .inst assembler bugs
arm64: alternative: Merge alternative-asm.h into alternative.h
arm64: Add AArch32 instruction set condition code checks
arm64: lib: use pair accessors for copy_*_user routines
arm64/uaccess: fix sparse errors
arm64: kernel: Move config_sctlr_el1
arm64: Emulate SETEND for AArch32 tasks
arm64: kconfig: move emulation option under kernel features
arm64: Consolidate hotplug notifier for instruction emulation
arm64: fix return code check when changing emulation handler
arm64: Trace emulation of AArch32 legacy instructions
arm64: Emulate CP15 Barrier instructions
arm64: Port SWP/SWPB emulation support from arm
...
Conflicts:
arch/arm64/kernel/Makefile
32 files changed, 1390 insertions, 101 deletions
diff --git a/Documentation/arm64/legacy_instructions.txt b/Documentation/arm64/legacy_instructions.txt new file mode 100644 index 000000000000..01bf3d9fac85 --- /dev/null +++ b/Documentation/arm64/legacy_instructions.txt @@ -0,0 +1,57 @@ +The arm64 port of the Linux kernel provides infrastructure to support +emulation of instructions which have been deprecated, or obsoleted in +the architecture. The infrastructure code uses undefined instruction +hooks to support emulation. Where available it also allows turning on +the instruction execution in hardware. + +The emulation mode can be controlled by writing to sysctl nodes +(/proc/sys/abi). The following explains the different execution +behaviours and the corresponding values of the sysctl nodes - + +* Undef + Value: 0 + Generates undefined instruction abort. Default for instructions that + have been obsoleted in the architecture, e.g., SWP + +* Emulate + Value: 1 + Uses software emulation. To aid migration of software, in this mode + usage of emulated instruction is traced as well as rate limited + warnings are issued. This is the default for deprecated + instructions, .e.g., CP15 barriers + +* Hardware Execution + Value: 2 + Although marked as deprecated, some implementations may support the + enabling/disabling of hardware support for the execution of these + instructions. Using hardware execution generally provides better + performance, but at the loss of ability to gather runtime statistics + about the use of the deprecated instructions. + +The default mode depends on the status of the instruction in the +architecture. Deprecated instructions should default to emulation +while obsolete instructions must be undefined by default. + +Note: Instruction emulation may not be possible in all cases. See +individual instruction notes for further information. + +Supported legacy instructions +----------------------------- +* SWP{B} +Node: /proc/sys/abi/swp +Status: Obsolete +Default: Undef (0) + +* CP15 Barriers +Node: /proc/sys/abi/cp15_barrier +Status: Deprecated +Default: Emulate (1) + +* SETEND +Node: /proc/sys/abi/setend +Status: Deprecated +Default: Emulate (1)* +Note: All the cpus on the system must have mixed endian support at EL0 +for this feature to be enabled. If a new CPU - which doesn't support mixed +endian - is hotplugged in after this feature has been enabled, there could +be unexpected results in the application. diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 611a8e75ac38..6595637c62c6 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -496,6 +496,87 @@ config FORCE_MAX_ZONEORDER default "14" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE) default "11" +config ARM64_PAN + bool "Enable support for Privileged Access Never (PAN)" + default y + help + Privileged Access Never (PAN; part of the ARMv8.1 Extensions) + prevents the kernel or hypervisor from accessing user-space (EL0) + memory directly. + + Choosing this option will cause any unprotected (not using + copy_to_user et al) memory access to fail with a permission fault. + + The feature is detected at runtime, and will remain as a 'nop' + instruction if the cpu does not implement the feature. + +menuconfig ARMV8_DEPRECATED + bool "Emulate deprecated/obsolete ARMv8 instructions" + depends on COMPAT + help + Legacy software support may require certain instructions + that have been deprecated or obsoleted in the architecture. + + Enable this config to enable selective emulation of these + features. + + If unsure, say Y + +if ARMV8_DEPRECATED + +config SWP_EMULATION + bool "Emulate SWP/SWPB instructions" + help + ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that + they are always undefined. Say Y here to enable software + emulation of these instructions for userspace using LDXR/STXR. + + In some older versions of glibc [<=2.8] SWP is used during futex + trylock() operations with the assumption that the code will not + be preempted. This invalid assumption may be more likely to fail + with SWP emulation enabled, leading to deadlock of the user + application. + + NOTE: when accessing uncached shared regions, LDXR/STXR rely + on an external transaction monitoring block called a global + monitor to maintain update atomicity. If your system does not + implement a global monitor, this option can cause programs that + perform SWP operations to uncached memory to deadlock. + + If unsure, say Y + +config CP15_BARRIER_EMULATION + bool "Emulate CP15 Barrier instructions" + help + The CP15 barrier instructions - CP15ISB, CP15DSB, and + CP15DMB - are deprecated in ARMv8 (and ARMv7). It is + strongly recommended to use the ISB, DSB, and DMB + instructions instead. + + Say Y here to enable software emulation of these + instructions for AArch32 userspace code. When this option is + enabled, CP15 barrier usage is traced which can help + identify software that needs updating. + + If unsure, say Y + +config SETEND_EMULATION + bool "Emulate SETEND instruction" + help + The SETEND instruction alters the data-endianness of the + AArch32 EL0, and is deprecated in ARMv8. + + Say Y here to enable software emulation of the instruction + for AArch32 userspace code. + + Note: All the cpus on the system must have mixed endian support at EL0 + for this feature to be enabled. If a new CPU - which doesn't support mixed + endian - is hotplugged in after this feature has been enabled, there could + be unexpected results in the applications. + + If unsure, say Y +endif + endmenu menu "Boot options" diff --git a/arch/arm64/include/asm/alternative-asm.h b/arch/arm64/include/asm/alternative-asm.h deleted file mode 100644 index 919a67855b63..000000000000 --- a/arch/arm64/include/asm/alternative-asm.h +++ /dev/null @@ -1,29 +0,0 @@ -#ifndef __ASM_ALTERNATIVE_ASM_H -#define __ASM_ALTERNATIVE_ASM_H - -#ifdef __ASSEMBLY__ - -.macro altinstruction_entry orig_offset alt_offset feature orig_len alt_len - .word \orig_offset - . - .word \alt_offset - . - .hword \feature - .byte \orig_len - .byte \alt_len -.endm - -.macro alternative_insn insn1 insn2 cap -661: \insn1 -662: .pushsection .altinstructions, "a" - altinstruction_entry 661b, 663f, \cap, 662b-661b, 664f-663f - .popsection - .pushsection .altinstr_replacement, "ax" -663: \insn2 -664: .popsection - .if ((664b-663b) != (662b-661b)) - .error "Alternatives instruction length mismatch" - .endif -.endm - -#endif /* __ASSEMBLY__ */ - -#endif /* __ASM_ALTERNATIVE_ASM_H */ diff --git a/arch/arm64/include/asm/alternative.h b/arch/arm64/include/asm/alternative.h index f6d206e7f9e9..4e3d4c8b50d1 100644 --- a/arch/arm64/include/asm/alternative.h +++ b/arch/arm64/include/asm/alternative.h @@ -1,6 +1,9 @@ #ifndef __ASM_ALTERNATIVE_H #define __ASM_ALTERNATIVE_H +#ifndef __ASSEMBLY__ + +#include <linux/kconfig.h> #include <linux/types.h> #include <linux/stddef.h> #include <linux/stringify.h> @@ -23,8 +26,22 @@ void free_alternatives_memory(void); " .byte 662b-661b\n" /* source len */ \ " .byte 664f-663f\n" /* replacement len */ -/* alternative assembly primitive: */ -#define ALTERNATIVE(oldinstr, newinstr, feature) \ +/* + * alternative assembly primitive: + * + * If any of these .org directive fail, it means that insn1 and insn2 + * don't have the same length. This used to be written as + * + * .if ((664b-663b) != (662b-661b)) + * .error "Alternatives instruction length mismatch" + * .endif + * + * but most assemblers die if insn1 or insn2 have a .inst. This should + * be fixed in a binutils release posterior to 2.25.51.0.2 (anything + * containing commit 4e4d08cf7399b606 or c1baaddf8861). + */ +#define __ALTERNATIVE_CFG(oldinstr, newinstr, feature, cfg_enabled) \ + ".if "__stringify(cfg_enabled)" == 1\n" \ "661:\n\t" \ oldinstr "\n" \ "662:\n" \ @@ -36,8 +53,92 @@ void free_alternatives_memory(void); newinstr "\n" \ "664:\n\t" \ ".popsection\n\t" \ - ".if ((664b-663b) != (662b-661b))\n\t" \ - " .error \"Alternatives instruction length mismatch\"\n\t"\ + ".org . - (664b-663b) + (662b-661b)\n\t" \ + ".org . - (662b-661b) + (664b-663b)\n" \ ".endif\n" +#define _ALTERNATIVE_CFG(oldinstr, newinstr, feature, cfg, ...) \ + __ALTERNATIVE_CFG(oldinstr, newinstr, feature, IS_ENABLED(cfg)) + +#else + +.macro altinstruction_entry orig_offset alt_offset feature orig_len alt_len + .word \orig_offset - . + .word \alt_offset - . + .hword \feature + .byte \orig_len + .byte \alt_len +.endm + +.macro alternative_insn insn1, insn2, cap, enable = 1 + .if \enable +661: \insn1 +662: .pushsection .altinstructions, "a" + altinstruction_entry 661b, 663f, \cap, 662b-661b, 664f-663f + .popsection + .pushsection .altinstr_replacement, "ax" +663: \insn2 +664: .popsection + .org . - (664b-663b) + (662b-661b) + .org . - (662b-661b) + (664b-663b) + .endif +.endm + +/* + * Begin an alternative code sequence. + * + * The code that follows this macro will be assembled and linked as + * normal. There are no restrictions on this code. + */ +.macro alternative_if_not cap + .pushsection .altinstructions, "a" + altinstruction_entry 661f, 663f, \cap, 662f-661f, 664f-663f + .popsection +661: +.endm + +/* + * Provide the alternative code sequence. + * + * The code that follows this macro is assembled into a special + * section to be used for dynamic patching. Code that follows this + * macro must: + * + * 1. Be exactly the same length (in bytes) as the default code + * sequence. + * + * 2. Not contain a branch target that is used outside of the + * alternative sequence it is defined in (branches into an + * alternative sequence are not fixed up). + */ +.macro alternative_else +662: .pushsection .altinstr_replacement, "ax" +663: +.endm + +/* + * Complete an alternative code sequence. + */ +.macro alternative_endif +664: .popsection + .org . - (664b-663b) + (662b-661b) + .org . - (662b-661b) + (664b-663b) +.endm + +#define _ALTERNATIVE_CFG(insn1, insn2, cap, cfg, ...) \ + alternative_insn insn1, insn2, cap, IS_ENABLED(cfg) + + +#endif /* __ASSEMBLY__ */ + +/* + * Usage: asm(ALTERNATIVE(oldinstr, newinstr, feature)); + * + * Usage: asm(ALTERNATIVE(oldinstr, newinstr, feature, CONFIG_FOO)); + * N.B. If CONFIG_FOO is specified, but not selected, the whole block + * will be omitted, including oldinstr. + */ +#define ALTERNATIVE(oldinstr, newinstr, ...) \ + _ALTERNATIVE_CFG(oldinstr, newinstr, __VA_ARGS__, 1) + #endif /* __ASM_ALTERNATIVE_H */ diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index c008bae718eb..d71140b76773 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -24,12 +24,32 @@ #define ARM64_WORKAROUND_CLEAN_CACHE 0 #define ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE 1 #define ARM64_WORKAROUND_845719 2 +#define ARM64_HAS_SYSREG_GIC_CPUIF 3 +#define ARM64_HAS_PAN 4 -#define NCAPS 3 +#define ARM64_NCAPS 5 #ifndef __ASSEMBLY__ -extern DECLARE_BITMAP(cpu_hwcaps, NCAPS); +struct arm64_cpu_capabilities { + const char *desc; + u16 capability; + bool (*matches)(const struct arm64_cpu_capabilities *); + void (*enable)(void); + union { + struct { /* To be used for erratum handling only */ + u32 midr_model; + u32 midr_range_min, midr_range_max; + }; + + struct { /* Feature register checking */ + int field_pos; + int min_field_value; + }; + }; +}; + +extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS); static inline bool cpu_have_feature(unsigned int num) { @@ -38,21 +58,33 @@ static inline bool cpu_have_feature(unsigned int num) static inline bool cpus_have_cap(unsigned int num) { - if (num >= NCAPS) + if (num >= ARM64_NCAPS) return false; return test_bit(num, cpu_hwcaps); } static inline void cpus_set_cap(unsigned int num) { - if (num >= NCAPS) + if (num >= ARM64_NCAPS) pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n", - num, NCAPS); + num, ARM64_NCAPS); else __set_bit(num, cpu_hwcaps); } +static inline int __attribute_const__ cpuid_feature_extract_field(u64 features, + int field) +{ + return (s64)(features << (64 - 4 - field)) >> (64 - 4); +} + + +void check_cpu_capabilities(const struct arm64_cpu_capabilities *caps, + const char *info); void check_local_cpu_errata(void); +void check_local_cpu_features(void); +bool cpu_supports_mixed_endian_el0(void); +bool system_supports_mixed_endian_el0(void); #endif /* __ASSEMBLY__ */ diff --git a/arch/arm64/include/asm/cputype.h b/arch/arm64/include/asm/cputype.h index 8adb986a3086..ee6403df9fe4 100644 --- a/arch/arm64/include/asm/cputype.h +++ b/arch/arm64/include/asm/cputype.h @@ -72,6 +72,15 @@ #define APM_CPU_PART_POTENZA 0x000 +#define ID_AA64MMFR0_BIGENDEL0_SHIFT 16 +#define ID_AA64MMFR0_BIGENDEL0_MASK (0xf << ID_AA64MMFR0_BIGENDEL0_SHIFT) +#define ID_AA64MMFR0_BIGENDEL0(mmfr0) \ + (((mmfr0) & ID_AA64MMFR0_BIGENDEL0_MASK) >> ID_AA64MMFR0_BIGENDEL0_SHIFT) +#define ID_AA64MMFR0_BIGEND_SHIFT 8 +#define ID_AA64MMFR0_BIGEND_MASK (0xf << ID_AA64MMFR0_BIGEND_SHIFT) +#define ID_AA64MMFR0_BIGEND(mmfr0) \ + (((mmfr0) & ID_AA64MMFR0_BIGEND_MASK) >> ID_AA64MMFR0_BIGEND_SHIFT) + #ifndef __ASSEMBLY__ /* @@ -104,6 +113,11 @@ static inline u32 __attribute_const__ read_cpuid_cachetype(void) return read_cpuid(CTR_EL0); } +static inline bool id_aa64mmfr0_mixed_endian_el0(u64 mmfr0) +{ + return (ID_AA64MMFR0_BIGEND(mmfr0) == 0x1) || + (ID_AA64MMFR0_BIGENDEL0(mmfr0) == 0x1); +} #endif /* __ASSEMBLY__ */ #endif diff --git a/arch/arm64/include/asm/futex.h b/arch/arm64/include/asm/futex.h index 5f750dc96e0f..667346273d9b 100644 --- a/arch/arm64/include/asm/futex.h +++ b/arch/arm64/include/asm/futex.h @@ -20,10 +20,16 @@ #include <linux/futex.h> #include <linux/uaccess.h> + +#include <asm/alternative.h> +#include <asm/cpufeature.h> #include <asm/errno.h> +#include <asm/sysreg.h> #define __futex_atomic_op(insn, ret, oldval, uaddr, tmp, oparg) \ asm volatile( \ + ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN, \ + CONFIG_ARM64_PAN) \ "1: ldxr %w1, %2\n" \ insn "\n" \ "2: stlxr %w3, %w0, %2\n" \ @@ -39,6 +45,8 @@ " .align 3\n" \ " .quad 1b, 4b, 2b, 4b\n" \ " .popsection\n" \ + ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN, \ + CONFIG_ARM64_PAN) \ : "=&r" (ret), "=&r" (oldval), "+Q" (*uaddr), "=&r" (tmp) \ : "r" (oparg), "Ir" (-EFAULT) \ : "memory") diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h index 56a9e63b6c33..e2ff32a93b5c 100644 --- a/arch/arm64/include/asm/insn.h +++ b/arch/arm64/include/asm/insn.h @@ -354,6 +354,16 @@ bool aarch64_insn_hotpatch_safe(u32 old_insn, u32 new_insn); int aarch64_insn_patch_text_nosync(void *addr, u32 insn); int aarch64_insn_patch_text_sync(void *addrs[], u32 insns[], int cnt); int aarch64_insn_patch_text(void *addrs[], u32 insns[], int cnt); + +bool aarch32_insn_is_wide(u32 insn); + +#define A32_RN_OFFSET 16 +#define A32_RT_OFFSET 12 +#define A32_RT2_OFFSET 0 + +u32 aarch32_insn_extract_reg_num(u32 insn, int offset); +u32 aarch32_insn_mcr_extract_opc2(u32 insn); +u32 aarch32_insn_mcr_extract_crm(u32 insn); #endif /* __ASSEMBLY__ */ #endif /* __ASM_INSN_H */ diff --git a/arch/arm64/include/asm/opcodes.h b/arch/arm64/include/asm/opcodes.h new file mode 100644 index 000000000000..4e603ea36ad3 --- /dev/null +++ b/arch/arm64/include/asm/opcodes.h @@ -0,0 +1 @@ +#include <../../arm/include/asm/opcodes.h> diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index 286b1bec547c..f3a965ed5259 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -166,4 +166,6 @@ static inline void spin_lock_prefetch(const void *x) #endif +void cpu_enable_pan(void); + #endif /* __ASM_PROCESSOR_H */ diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h index 41ed9e13795e..d6dd9fdbc3be 100644 --- a/arch/arm64/include/asm/ptrace.h +++ b/arch/arm64/include/asm/ptrace.h @@ -58,6 +58,13 @@ #define COMPAT_PSR_Z_BIT 0x40000000 #define COMPAT_PSR_N_BIT 0x80000000 #define COMPAT_PSR_IT_MASK 0x0600fc00 /* If-Then execution state mask */ + +#ifdef CONFIG_CPU_BIG_ENDIAN +#define COMPAT_PSR_ENDSTATE COMPAT_PSR_E_BIT +#else +#define COMPAT_PSR_ENDSTATE 0 +#endif + /* * These are 'magic' values for PTRACE_PEEKUSR that return info about where a * process is located in memory. diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h index 5c89df0acbcb..a7f3d4b2514d 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -20,8 +20,29 @@ #ifndef __ASM_SYSREG_H #define __ASM_SYSREG_H +#include <asm/opcodes.h> + +#define SCTLR_EL1_CP15BEN (0x1 << 5) +#define SCTLR_EL1_SED (0x1 << 8) + +/* + * ARMv8 ARM reserves the following encoding for system registers: + * (Ref: ARMv8 ARM, Section: "System instruction class encoding overview", + * C5.2, version:ARM DDI 0487A.f) + * [20-19] : Op0 + * [18-16] : Op1 + * [15-12] : CRn + * [11-8] : CRm + * [7-5] : Op2 + */ #define sys_reg(op0, op1, crn, crm, op2) \ - ((((op0)-2)<<19)|((op1)<<16)|((crn)<<12)|((crm)<<8)|((op2)<<5)) + ((((op0)&3)<<19)|((op1)<<16)|((crn)<<12)|((crm)<<8)|((op2)<<5)) + +#define REG_PSTATE_PAN_IMM sys_reg(0, 0, 4, 0, 4) +#define SCTLR_EL1_SPAN (1 << 23) + +#define SET_PSTATE_PAN(x) __inst_arm(0xd5000000 | REG_PSTATE_PAN_IMM |\ + (!!x)<<8 | 0x1f) #ifdef __ASSEMBLY__ @@ -31,11 +52,11 @@ .equ __reg_num_xzr, 31 .macro mrs_s, rt, sreg - .inst 0xd5300000|(\sreg)|(__reg_num_\rt) + .inst 0xd5200000|(\sreg)|(__reg_num_\rt) .endm .macro msr_s, sreg, rt - .inst 0xd5100000|(\sreg)|(__reg_num_\rt) + .inst 0xd5000000|(\sreg)|(__reg_num_\rt) .endm #else @@ -47,14 +68,23 @@ asm( " .equ __reg_num_xzr, 31\n" "\n" " .macro mrs_s, rt, sreg\n" -" .inst 0xd5300000|(\\sreg)|(__reg_num_\\rt)\n" +" .inst 0xd5200000|(\\sreg)|(__reg_num_\\rt)\n" " .endm\n" "\n" " .macro msr_s, sreg, rt\n" -" .inst 0xd5100000|(\\sreg)|(__reg_num_\\rt)\n" +" .inst 0xd5000000|(\\sreg)|(__reg_num_\\rt)\n" " .endm\n" ); +static inline void config_sctlr_el1(u32 clear, u32 set) +{ + u32 val; + + asm volatile("mrs %0, sctlr_el1" : "=r" (val)); + val &= ~clear; + val |= set; + asm volatile("msr sctlr_el1, %0" : : "r" (val)); +} #endif #endif /* __ASM_SYSREG_H */ diff --git a/arch/arm64/include/asm/traps.h b/arch/arm64/include/asm/traps.h index 10ca8ff93cc2..232e4ba5d314 100644 --- a/arch/arm64/include/asm/traps.h +++ b/arch/arm64/include/asm/traps.h @@ -18,6 +18,22 @@ #ifndef __ASM_TRAP_H #define __ASM_TRAP_H +#include <linux/list.h> + +struct pt_regs; + +struct undef_hook { + struct list_head node; + u32 instr_mask; + u32 instr_val; + u64 pstate_mask; + u64 pstate_val; + int (*fn)(struct pt_regs *regs, u32 instr); +}; + +void register_undef_hook(struct undef_hook *hook); +void unregister_undef_hook(struct undef_hook *hook); + static inline int in_exception_text(unsigned long ptr) { extern char __exception_text_start[]; diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index 3bf8f4e99a51..cb8dab4257a2 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -24,7 +24,10 @@ #include <linux/string.h> #include <linux/thread_info.h> +#include <asm/alternative.h> +#include <asm/cpufeature.h> #include <asm/ptrace.h> +#include <asm/sysreg.h> #include <asm/errno.h> #include <asm/memory.h> #include <asm/compiler.h> @@ -131,6 +134,8 @@ static inline void set_fs(mm_segment_t fs) do { \ unsigned long __gu_val; \ __chk_user_ptr(ptr); \ + asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN, \ + CONFIG_ARM64_PAN)); \ switch (sizeof(*(ptr))) { \ case 1: \ __get_user_asm("ldrb", "%w", __gu_val, (ptr), (err)); \ @@ -147,7 +152,9 @@ do { \ default: \ BUILD_BUG(); \ } \ - (x) = (__typeof__(*(ptr)))__gu_val; \ + (x) = (__force __typeof__(*(ptr)))__gu_val; \ + asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN, \ + CONFIG_ARM64_PAN)); \ } while (0) #define __get_user(x, ptr) \ @@ -194,6 +201,8 @@ do { \ do { \ __typeof__(*(ptr)) __pu_val = (x); \ __chk_user_ptr(ptr); \ + asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN, \ + CONFIG_ARM64_PAN)); \ switch (sizeof(*(ptr))) { \ case 1: \ __put_user_asm("strb", "%w", __pu_val, (ptr), (err)); \ @@ -210,6 +219,8 @@ do { \ default: \ BUILD_BUG(); \ } \ + asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN, \ + CONFIG_ARM64_PAN)); \ } while (0) #define __put_user(x, ptr) \ diff --git a/arch/arm64/include/uapi/asm/ptrace.h b/arch/arm64/include/uapi/asm/ptrace.h index 6913643bbe54..208db3df135a 100644 --- a/arch/arm64/include/uapi/asm/ptrace.h +++ b/arch/arm64/include/uapi/asm/ptrace.h @@ -44,6 +44,7 @@ #define PSR_I_BIT 0x00000080 #define PSR_A_BIT 0x00000100 #define PSR_D_BIT 0x00000200 +#define PSR_PAN_BIT 0x00400000 #define PSR_Q_BIT 0x08000000 #define PSR_V_BIT 0x10000000 #define PSR_C_BIT 0x20000000 diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index eccb8c7cb30f..a31374cb8627 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -5,6 +5,7 @@ CPPFLAGS_vmlinux.lds := -DTEXT_OFFSET=$(TEXT_OFFSET) AFLAGS_head.o := -DTEXT_OFFSET=$(TEXT_OFFSET) CFLAGS_efi-stub.o := -DTEXT_OFFSET=$(TEXT_OFFSET) +CFLAGS_armv8_deprecated.o := -I$(src) CFLAGS_REMOVE_ftrace.o = -pg CFLAGS_REMOVE_insn.o = -pg @@ -14,11 +15,12 @@ CFLAGS_REMOVE_return_address.o = -pg arm64-obj-y := cputable.o debug-monitors.o entry.o irq.o fpsimd.o \ entry-fpsimd.o process.o ptrace.o setup.o signal.o \ sys.o stacktrace.o time.o traps.o io.o vdso.o \ - hyp-stub.o psci.o psci-call.o cpu_ops.o insn.o \ - return_address.o cpuinfo.o cpu_errata.o alternative.o + hyp-stub.o psci.o psci-call.o cpu_ops.o insn.o \ + return_address.o cpuinfo.o cpu_errata.o cpufeature.o alternative.o arm64-obj-$(CONFIG_COMPAT) += sys32.o kuser32.o signal32.o \ - sys_compat.o + sys_compat.o \ + ../../arm/kernel/opcodes.o arm64-obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o entry-ftrace.o arm64-obj-$(CONFIG_MODULES) += arm64ksyms.o module.o arm64-obj-$(CONFIG_SMP) += smp.o smp_spin_table.o topology.o @@ -31,6 +33,7 @@ arm64-obj-$(CONFIG_JUMP_LABEL) += jump_label.o arm64-obj-$(CONFIG_KGDB) += kgdb.o arm64-obj-$(CONFIG_EFI) += efi.o efi-stub.o efi-entry.o arm64-obj-$(CONFIG_PCI) += pci.o +arm64-obj-$(CONFIG_ARMV8_DEPRECATED) += armv8_deprecated.o obj-y += $(arm64-obj-y) vdso/ obj-m += $(arm64-obj-m) diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c new file mode 100644 index 000000000000..bcee7abac68e --- /dev/null +++ b/arch/arm64/kernel/armv8_deprecated.c @@ -0,0 +1,659 @@ +/* + * Copyright (C) 2014 ARM Limited + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/cpu.h> +#include <linux/init.h> +#include <linux/list.h> +#include <linux/perf_event.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/sysctl.h> + +#include <asm/alternative.h> +#include <asm/cpufeature.h> +#include <asm/insn.h> +#include <asm/opcodes.h> +#include <asm/sysreg.h> +#include <asm/system_misc.h> +#include <asm/traps.h> +#include <asm/uaccess.h> +#include <asm/cpufeature.h> + +#define CREATE_TRACE_POINTS +#include "trace-events-emulation.h" + +/* + * The runtime support for deprecated instruction support can be in one of + * following three states - + * + * 0 = undef + * 1 = emulate (software emulation) + * 2 = hw (supported in hardware) + */ +enum insn_emulation_mode { + INSN_UNDEF, + INSN_EMULATE, + INSN_HW, +}; + +enum legacy_insn_status { + INSN_DEPRECATED, + INSN_OBSOLETE, +}; + +struct insn_emulation_ops { + const char *name; + enum legacy_insn_status status; + struct undef_hook *hooks; + int (*set_hw_mode)(bool enable); +}; + +struct insn_emulation { + struct list_head node; + struct insn_emulation_ops *ops; + int current_mode; + int min; + int max; +}; + +static LIST_HEAD(insn_emulation); +static int nr_insn_emulated; +static DEFINE_RAW_SPINLOCK(insn_emulation_lock); + +static void register_emulation_hooks(struct insn_emulation_ops *ops) +{ + struct undef_hook *hook; + + BUG_ON(!ops->hooks); + + for (hook = ops->hooks; hook->instr_mask; hook++) + register_undef_hook(hook); + + pr_notice("Registered %s emulation handler\n", ops->name); +} + +static void remove_emulation_hooks(struct insn_emulation_ops *ops) +{ + struct undef_hook *hook; + + BUG_ON(!ops->hooks); + + for (hook = ops->hooks; hook->instr_mask; hook++) + unregister_undef_hook(hook); + + pr_notice("Removed %s emulation handler\n", ops->name); +} + +static void enable_insn_hw_mode(void *data) +{ + struct insn_emulation *insn = (struct insn_emulation *)data; + if (insn->ops->set_hw_mode) + insn->ops->set_hw_mode(true); +} + +static void disable_insn_hw_mode(void *data) +{ + struct insn_emulation *insn = (struct insn_emulation *)data; + if (insn->ops->set_hw_mode) + insn->ops->set_hw_mode(false); +} + +/* Run set_hw_mode(mode) on all active CPUs */ +static int run_all_cpu_set_hw_mode(struct insn_emulation *insn, bool enable) +{ + if (!insn->ops->set_hw_mode) + return -EINVAL; + if (enable) + on_each_cpu(enable_insn_hw_mode, (void *)insn, true); + else + on_each_cpu(disable_insn_hw_mode, (void *)insn, true); + return 0; +} + +/* + * Run set_hw_mode for all insns on a starting CPU. + * Returns: + * 0 - If all the hooks ran successfully. + * -EINVAL - At least one hook is not supported by the CPU. + */ +static int run_all_insn_set_hw_mode(unsigned long cpu) +{ + int rc = 0; + unsigned long flags; + struct insn_emulation *insn; + + raw_spin_lock_irqsave(&insn_emulation_lock, flags); + list_for_each_entry(insn, &insn_emulation, node) { + bool enable = (insn->current_mode == INSN_HW); + if (insn->ops->set_hw_mode && insn->ops->set_hw_mode(enable)) { + pr_warn("CPU[%ld] cannot support the emulation of %s", + cpu, insn->ops->name); + rc = -EINVAL; + } + } + raw_spin_unlock_irqrestore(&insn_emulation_lock, flags); + return rc; +} + +static int update_insn_emulation_mode(struct insn_emulation *insn, + enum insn_emulation_mode prev) +{ + int ret = 0; + + switch (prev) { + case INSN_UNDEF: /* Nothing to be done */ + break; + case INSN_EMULATE: + remove_emulation_hooks(insn->ops); + break; + case INSN_HW: + if (!run_all_cpu_set_hw_mode(insn, false)) + pr_notice("Disabled %s support\n", insn->ops->name); + break; + } + + switch (insn->current_mode) { + case INSN_UNDEF: + break; + case INSN_EMULATE: + register_emulation_hooks(insn->ops); + break; + case INSN_HW: + ret = run_all_cpu_set_hw_mode(insn, true); + if (!ret) + pr_notice("Enabled %s support\n", insn->ops->name); + break; + } + + return ret; +} + +static void register_insn_emulation(struct insn_emulation_ops *ops) +{ + unsigned long flags; + struct insn_emulation *insn; + + insn = kzalloc(sizeof(*insn), GFP_KERNEL); + insn->ops = ops; + insn->min = INSN_UNDEF; + + switch (ops->status) { + case INSN_DEPRECATED: + insn->current_mode = INSN_EMULATE; + /* Disable the HW mode if it was turned on at early boot time */ + run_all_cpu_set_hw_mode(insn, false); + insn->max = INSN_HW; + break; + case INSN_OBSOLETE: + insn->current_mode = INSN_UNDEF; + insn->max = INSN_EMULATE; + break; + } + + raw_spin_lock_irqsave(&insn_emulation_lock, flags); + list_add(&insn->node, &insn_emulation); + nr_insn_emulated++; + raw_spin_unlock_irqrestore(&insn_emulation_lock, flags); + + /* Register any handlers if required */ + update_insn_emulation_mode(insn, INSN_UNDEF); +} + +static int emulation_proc_handler(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, + loff_t *ppos) +{ + int ret = 0; + struct insn_emulation *insn = (struct insn_emulation *) table->data; + enum insn_emulation_mode prev_mode = insn->current_mode; + + table->data = &insn->current_mode; + ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); + + if (ret || !write || prev_mode == insn->current_mode) + goto ret; + + ret = update_insn_emulation_mode(insn, prev_mode); + if (ret) { + /* Mode change failed, revert to previous mode. */ + insn->current_mode = prev_mode; + update_insn_emulation_mode(insn, INSN_UNDEF); + } +ret: + table->data = insn; + return ret; +} + +static struct ctl_table ctl_abi[] = { + { + .procname = "abi", + .mode = 0555, + }, + { } +}; + +static void register_insn_emulation_sysctl(struct ctl_table *table) +{ + unsigned long flags; + int i = 0; + struct insn_emulation *insn; + struct ctl_table *insns_sysctl, *sysctl; + + insns_sysctl = kzalloc(sizeof(*sysctl) * (nr_insn_emulated + 1), + GFP_KERNEL); + + raw_spin_lock_irqsave(&insn_emulation_lock, flags); + list_for_each_entry(insn, &insn_emulation, node) { + sysctl = &insns_sysctl[i]; + + sysctl->mode = 0644; + sysctl->maxlen = sizeof(int); + + sysctl->procname = insn->ops->name; + sysctl->data = insn; + sysctl->extra1 = &insn->min; + sysctl->extra2 = &insn->max; + sysctl->proc_handler = emulation_proc_handler; + i++; + } + raw_spin_unlock_irqrestore(&insn_emulation_lock, flags); + + table->child = insns_sysctl; + register_sysctl_table(table); +} + +/* + * Implement emulation of the SWP/SWPB instructions using load-exclusive and + * store-exclusive. + * + * Syntax of SWP{B} instruction: SWP{B}<c> <Rt>, <Rt2>, [<Rn>] + * Where: Rt = destination + * Rt2 = source + * Rn = address + */ + +/* + * Error-checking SWP macros implemented using ldxr{b}/stxr{b} + */ +#define __user_swpX_asm(data, addr, res, temp, B) \ + __asm__ __volatile__( \ + ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN, \ + CONFIG_ARM64_PAN) \ + " mov %w2, %w1\n" \ + "0: ldxr"B" %w1, [%3]\n" \ + "1: stxr"B" %w0, %w2, [%3]\n" \ + " cbz %w0, 2f\n" \ + " mov %w0, %w4\n" \ + "2:\n" \ + " .pushsection .fixup,\"ax\"\n" \ + " .align 2\n" \ + "3: mov %w0, %w5\n" \ + " b 2b\n" \ + " .popsection" \ + " .pushsection __ex_table,\"a\"\n" \ + " .align 3\n" \ + " .quad 0b, 3b\n" \ + " .quad 1b, 3b\n" \ + " .popsection\n" \ + ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN, \ + CONFIG_ARM64_PAN) \ + : "=&r" (res), "+r" (data), "=&r" (temp) \ + : "r" (addr), "i" (-EAGAIN), "i" (-EFAULT) \ + : "memory") + +#define __user_swp_asm(data, addr, res, temp) \ + __user_swpX_asm(data, addr, res, temp, "") +#define __user_swpb_asm(data, addr, res, temp) \ + __user_swpX_asm(data, addr, res, temp, "b") + +/* + * Bit 22 of the instruction encoding distinguishes between + * the SWP and SWPB variants (bit set means SWPB). + */ +#define TYPE_SWPB (1 << 22) + +/* + * Set up process info to signal segmentation fault - called on access error. + */ +static void set_segfault(struct pt_regs *regs, unsigned long addr) +{ + siginfo_t info; + + down_read(¤t->mm->mmap_sem); + if (find_vma(current->mm, addr) == NULL) + info.si_code = SEGV_MAPERR; + else + info.si_code = SEGV_ACCERR; + up_read(¤t->mm->mmap_sem); + + info.si_signo = SIGSEGV; + info.si_errno = 0; + info.si_addr = (void *) instruction_pointer(regs); + + pr_debug("SWP{B} emulation: access caused memory abort!\n"); + arm64_notify_die("Illegal memory access", regs, &info, 0); +} + +static int emulate_swpX(unsigned int address, unsigned int *data, + unsigned int type) +{ + unsigned int res = 0; + + if ((type != TYPE_SWPB) && (address & 0x3)) { + /* SWP to unaligned address not permitted */ + pr_debug("SWP instruction on unaligned pointer!\n"); + return -EFAULT; + } + + while (1) { + unsigned long temp; + + if (type == TYPE_SWPB) + __user_swpb_asm(*data, address, res, temp); + else + __user_swp_asm(*data, address, res, temp); + + if (likely(res != -EAGAIN) || signal_pending(current)) + break; + + cond_resched(); + } + + return res; +} + +/* + * swp_handler logs the id of calling process, dissects the instruction, sanity + * checks the memory location, calls emulate_swpX for the actual operation and + * deals with fixup/error handling before returning + */ +static int swp_handler(struct pt_regs *regs, u32 instr) +{ + u32 destreg, data, type, address = 0; + int rn, rt2, res = 0; + + perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, regs->pc); + + type = instr & TYPE_SWPB; + + switch (arm_check_condition(instr, regs->pstate)) { + case ARM_OPCODE_CONDTEST_PASS: + break; + case ARM_OPCODE_CONDTEST_FAIL: + /* Condition failed - return to next instruction */ + goto ret; + case ARM_OPCODE_CONDTEST_UNCOND: + /* If unconditional encoding - not a SWP, undef */ + return -EFAULT; + default: + return -EINVAL; + } + + rn = aarch32_insn_extract_reg_num(instr, A32_RN_OFFSET); + rt2 = aarch32_insn_extract_reg_num(instr, A32_RT2_OFFSET); + + address = (u32)regs->user_regs.regs[rn]; + data = (u32)regs->user_regs.regs[rt2]; + destreg = aarch32_insn_extract_reg_num(instr, A32_RT_OFFSET); + + pr_debug("addr in r%d->0x%08x, dest is r%d, source in r%d->0x%08x)\n", + rn, address, destreg, + aarch32_insn_extract_reg_num(instr, A32_RT2_OFFSET), data); + + /* Check access in reasonable access range for both SWP and SWPB */ + if (!access_ok(VERIFY_WRITE, (address & ~3), 4)) { + pr_debug("SWP{B} emulation: access to 0x%08x not allowed!\n", + address); + goto fault; + } + + res = emulate_swpX(address, &data, type); + if (res == -EFAULT) + goto fault; + else if (res == 0) + regs->user_regs.regs[destreg] = data; + +ret: + if (type == TYPE_SWPB) + trace_instruction_emulation("swpb", regs->pc); + else + trace_instruction_emulation("swp", regs->pc); + + pr_warn_ratelimited("\"%s\" (%ld) uses obsolete SWP{B} instruction at 0x%llx\n", + current->comm, (unsigned long)current->pid, regs->pc); + + regs->pc += 4; + return 0; + +fault: + set_segfault(regs, address); + + return 0; +} + +/* + * Only emulate SWP/SWPB executed in ARM state/User mode. + * The kernel must be SWP free and SWP{B} does not exist in Thumb. + */ +static struct undef_hook swp_hooks[] = { + { + .instr_mask = 0x0fb00ff0, + .instr_val = 0x01000090, + .pstate_mask = COMPAT_PSR_MODE_MASK, + .pstate_val = COMPAT_PSR_MODE_USR, + .fn = swp_handler + }, + { } +}; + +static struct insn_emulation_ops swp_ops = { + .name = "swp", + .status = INSN_OBSOLETE, + .hooks = swp_hooks, + .set_hw_mode = NULL, +}; + +static int cp15barrier_handler(struct pt_regs *regs, u32 instr) +{ + perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, regs->pc); + + switch (arm_check_condition(instr, regs->pstate)) { + case ARM_OPCODE_CONDTEST_PASS: + break; + case ARM_OPCODE_CONDTEST_FAIL: + /* Condition failed - return to next instruction */ + goto ret; + case ARM_OPCODE_CONDTEST_UNCOND: + /* If unconditional encoding - not a barrier instruction */ + return -EFAULT; + default: + return -EINVAL; + } + + switch (aarch32_insn_mcr_extract_crm(instr)) { + case 10: + /* + * dmb - mcr p15, 0, Rt, c7, c10, 5 + * dsb - mcr p15, 0, Rt, c7, c10, 4 + */ + if (aarch32_insn_mcr_extract_opc2(instr) == 5) { + dmb(sy); + trace_instruction_emulation( + "mcr p15, 0, Rt, c7, c10, 5 ; dmb", regs->pc); + } else { + dsb(sy); + trace_instruction_emulation( + "mcr p15, 0, Rt, c7, c10, 4 ; dsb", regs->pc); + } + break; + case 5: + /* + * isb - mcr p15, 0, Rt, c7, c5, 4 + * + * Taking an exception or returning from one acts as an + * instruction barrier. So no explicit barrier needed here. + */ + trace_instruction_emulation( + "mcr p15, 0, Rt, c7, c5, 4 ; isb", regs->pc); + break; + } + +ret: + pr_warn_ratelimited("\"%s\" (%ld) uses deprecated CP15 Barrier instruction at 0x%llx\n", + current->comm, (unsigned long)current->pid, regs->pc); + + regs->pc += 4; + return 0; +} + +static int cp15_barrier_set_hw_mode(bool enable) +{ + if (enable) + config_sctlr_el1(0, SCTLR_EL1_CP15BEN); + else + config_sctlr_el1(SCTLR_EL1_CP15BEN, 0); + return 0; +} + +static struct undef_hook cp15_barrier_hooks[] = { + { + .instr_mask = 0x0fff0fdf, + .instr_val = 0x0e070f9a, + .pstate_mask = COMPAT_PSR_MODE_MASK, + .pstate_val = COMPAT_PSR_MODE_USR, + .fn = cp15barrier_handler, + }, + { + .instr_mask = 0x0fff0fff, + .instr_val = 0x0e070f95, + .pstate_mask = COMPAT_PSR_MODE_MASK, + .pstate_val = COMPAT_PSR_MODE_USR, + .fn = cp15barrier_handler, + }, + { } +}; + +static struct insn_emulation_ops cp15_barrier_ops = { + .name = "cp15_barrier", + .status = INSN_DEPRECATED, + .hooks = cp15_barrier_hooks, + .set_hw_mode = cp15_barrier_set_hw_mode, +}; + +static int setend_set_hw_mode(bool enable) +{ + if (!cpu_supports_mixed_endian_el0()) + return -EINVAL; + + if (enable) + config_sctlr_el1(SCTLR_EL1_SED, 0); + else + config_sctlr_el1(0, SCTLR_EL1_SED); + return 0; +} + +static int compat_setend_handler(struct pt_regs *regs, u32 big_endian) +{ + char *insn; + + perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, regs->pc); + + if (big_endian) { + insn = "setend be"; + regs->pstate |= COMPAT_PSR_E_BIT; + } else { + insn = "setend le"; + regs->pstate &= ~COMPAT_PSR_E_BIT; + } + + trace_instruction_emulation(insn, regs->pc); + pr_warn_ratelimited("\"%s\" (%ld) uses deprecated setend instruction at 0x%llx\n", + current->comm, (unsigned long)current->pid, regs->pc); + + return 0; +} + +static int a32_setend_handler(struct pt_regs *regs, u32 instr) +{ + int rc = compat_setend_handler(regs, (instr >> 9) & 1); + regs->pc += 4; + return rc; +} + +static int t16_setend_handler(struct pt_regs *regs, u32 instr) +{ + int rc = compat_setend_handler(regs, (instr >> 3) & 1); + regs->pc += 2; + return rc; +} + +static struct undef_hook setend_hooks[] = { + { + .instr_mask = 0xfffffdff, + .instr_val = 0xf1010000, + .pstate_mask = COMPAT_PSR_MODE_MASK, + .pstate_val = COMPAT_PSR_MODE_USR, + .fn = a32_setend_handler, + }, + { + /* Thumb mode */ + .instr_mask = 0x0000fff7, + .instr_val = 0x0000b650, + .pstate_mask = (COMPAT_PSR_T_BIT | COMPAT_PSR_MODE_MASK), + .pstate_val = (COMPAT_PSR_T_BIT | COMPAT_PSR_MODE_USR), + .fn = t16_setend_handler, + }, + {} +}; + +static struct insn_emulation_ops setend_ops = { + .name = "setend", + .status = INSN_DEPRECATED, + .hooks = setend_hooks, + .set_hw_mode = setend_set_hw_mode, +}; + +static int insn_cpu_hotplug_notify(struct notifier_block *b, + unsigned long action, void *hcpu) +{ + int rc = 0; + if ((action & ~CPU_TASKS_FROZEN) == CPU_STARTING) + rc = run_all_insn_set_hw_mode((unsigned long)hcpu); + + return notifier_from_errno(rc); +} + +static struct notifier_block insn_cpu_hotplug_notifier = { + .notifier_call = insn_cpu_hotplug_notify, +}; + +/* + * Invoked as late_initcall, since not needed before init spawned. + */ +static int __init armv8_deprecated_init(void) +{ + if (IS_ENABLED(CONFIG_SWP_EMULATION)) + register_insn_emulation(&swp_ops); + + if (IS_ENABLED(CONFIG_CP15_BARRIER_EMULATION)) + register_insn_emulation(&cp15_barrier_ops); + + if (IS_ENABLED(CONFIG_SETEND_EMULATION)) { + if(system_supports_mixed_endian_el0()) + register_insn_emulation(&setend_ops); + else + pr_info("setend instruction emulation is not supported on the system"); + } + + register_cpu_notifier(&insn_cpu_hotplug_notifier); + register_insn_emulation_sysctl(ctl_abi); + + return 0; +} + +late_initcall(armv8_deprecated_init); diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index bbc710aafb37..6ffd91438560 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -16,8 +16,6 @@ * along with this program. If not, see <http://www.gnu.org/licenses/>. */ -#define pr_fmt(fmt) "alternative: " fmt - #include <linux/types.h> #include <asm/cpu.h> #include <asm/cputype.h> @@ -26,27 +24,11 @@ #define MIDR_CORTEX_A53 MIDR_CPU_PART(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A53) #define MIDR_CORTEX_A57 MIDR_CPU_PART(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A57) -/* - * Add a struct or another datatype to the union below if you need - * different means to detect an affected CPU. - */ -struct arm64_cpu_capabilities { - const char *desc; - u16 capability; - bool (*is_affected)(struct arm64_cpu_capabilities *); - union { - struct { - u32 midr_model; - u32 midr_range_min, midr_range_max; - }; - }; -}; - #define CPU_MODEL_MASK (MIDR_IMPLEMENTOR_MASK | MIDR_PARTNUM_MASK | \ MIDR_ARCHITECTURE_MASK) static bool __maybe_unused -is_affected_midr_range(struct arm64_cpu_capabilities *entry) +is_affected_midr_range(const struct arm64_cpu_capabilities *entry) { u32 midr = read_cpuid_id(); @@ -59,12 +41,12 @@ is_affected_midr_range(struct arm64_cpu_capabilities *entry) } #define MIDR_RANGE(model, min, max) \ - .is_affected = is_affected_midr_range, \ + .matches = is_affected_midr_range, \ .midr_model = model, \ .midr_range_min = min, \ .midr_range_max = max -struct arm64_cpu_capabilities arm64_errata[] = { +const struct arm64_cpu_capabilities arm64_errata[] = { #if defined(CONFIG_ARM64_ERRATUM_826319) || \ defined(CONFIG_ARM64_ERRATUM_827319) || \ defined(CONFIG_ARM64_ERRATUM_824069) @@ -106,15 +88,5 @@ struct arm64_cpu_capabilities arm64_errata[] = { void check_local_cpu_errata(void) { - struct arm64_cpu_capabilities *cpus = arm64_errata; - int i; - - for (i = 0; cpus[i].desc; i++) { - if (!cpus[i].is_affected(&cpus[i])) - continue; - - if (!cpus_have_cap(cpus[i].capability)) - pr_info("enabling workaround for %s\n", cpus[i].desc); - cpus_set_cap(cpus[i].capability); - } + check_cpu_capabilities(arm64_errata, "enabling workaround for"); } diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c new file mode 100644 index 000000000000..978fa169d3c3 --- /dev/null +++ b/arch/arm64/kernel/cpufeature.c @@ -0,0 +1,97 @@ +/* + * Contains CPU feature definitions + * + * Copyright (C) 2015 ARM Ltd. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#define pr_fmt(fmt) "alternatives: " fmt + +#include <linux/types.h> +#include <asm/cpu.h> +#include <asm/cpufeature.h> +#include <asm/processor.h> + +static bool +feature_matches(u64 reg, const struct arm64_cpu_capabilities *entry) +{ + int val = cpuid_feature_extract_field(reg, entry->field_pos); + + return val >= entry->min_field_value; +} + +static bool +has_id_aa64pfr0_feature(const struct arm64_cpu_capabilities *entry) +{ + u64 val; + + val = read_cpuid(id_aa64pfr0_el1); + return feature_matches(val, entry); +} + +static bool __maybe_unused +has_id_aa64mmfr1_feature(const struct arm64_cpu_capabilities *entry) +{ + u64 val; + + val = read_cpuid(id_aa64mmfr1_el1); + return feature_matches(val, entry); +} + +static const struct arm64_cpu_capabilities arm64_features[] = { + { + .desc = "GIC system register CPU interface", + .capability = ARM64_HAS_SYSREG_GIC_CPUIF, + .matches = has_id_aa64pfr0_feature, + .field_pos = 24, + .min_field_value = 1, + }, +#ifdef CONFIG_ARM64_PAN + { + .desc = "Privileged Access Never", + .capability = ARM64_HAS_PAN, + .matches = has_id_aa64mmfr1_feature, + .field_pos = 20, + .min_field_value = 1, + .enable = cpu_enable_pan, + }, +#endif /* CONFIG_ARM64_PAN */ + {}, +}; + +void check_cpu_capabilities(const struct arm64_cpu_capabilities *caps, + const char *info) +{ + int i; + + for (i = 0; caps[i].desc; i++) { + if (!caps[i].matches(&caps[i])) + continue; + + if (!cpus_have_cap(caps[i].capability)) + pr_info("%s %s\n", info, caps[i].desc); + cpus_set_cap(caps[i].capability); + } + + /* second pass allows enable() to consider interacting capabilities */ + for (i = 0; caps[i].desc; i++) { + if (cpus_have_cap(caps[i].capability) && caps[i].enable) + caps[i].enable(); + } +} + +void check_local_cpu_features(void) +{ + check_cpu_capabilities(arm64_features, "detected feature"); +} diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c index 16d6d032ecf1..faf5cadbd391 100644 --- a/arch/arm64/kernel/cpuinfo.c +++ b/arch/arm64/kernel/cpuinfo.c @@ -35,6 +35,7 @@ */ DEFINE_PER_CPU(struct cpuinfo_arm64, cpu_data); static struct cpuinfo_arm64 boot_cpu_data; +static bool mixed_endian_el0 = true; static char *icache_policy_str[] = { [ICACHE_POLICY_RESERVED] = "RESERVED/UNKNOWN", @@ -68,6 +69,26 @@ static void cpuinfo_detect_icache_policy(struct cpuinfo_arm64 *info) pr_info("Detected %s I-cache on CPU%d\n", icache_policy_str[l1ip], cpu); } +bool cpu_supports_mixed_endian_el0(void) +{ + return id_aa64mmfr0_mixed_endian_el0(read_cpuid(ID_AA64MMFR0_EL1)); +} + +bool system_supports_mixed_endian_el0(void) +{ + return mixed_endian_el0; +} + +static void update_mixed_endian_el0_support(struct cpuinfo_arm64 *info) +{ + mixed_endian_el0 &= id_aa64mmfr0_mixed_endian_el0(info->reg_id_aa64mmfr0); +} + +static void update_cpu_features(struct cpuinfo_arm64 *info) +{ + update_mixed_endian_el0_support(info); +} + static int check_reg_mask(char *name, u64 mask, u64 boot, u64 cur, int cpu) { if ((boot & mask) == (cur & mask)) @@ -189,6 +210,8 @@ static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info) cpuinfo_detect_icache_policy(info); check_local_cpu_errata(); + check_local_cpu_features(); + update_cpu_features(info); } void cpuinfo_store_cpu(void) diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 6c99b4664b40..b5d2f23e4f86 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -21,7 +21,7 @@ #include <linux/init.h> #include <linux/linkage.h> -#include <asm/alternative-asm.h> +#include <asm/alternative.h> #include <asm/assembler.h> #include <asm/asm-offsets.h> #include <asm/cpufeature.h> diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c index 8cd27fedc8b6..7e9327a0986d 100644 --- a/arch/arm64/kernel/insn.c +++ b/arch/arm64/kernel/insn.c @@ -960,3 +960,29 @@ u32 aarch64_insn_gen_logical_shifted_reg(enum aarch64_insn_register dst, return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_6, insn, shift); } + +bool aarch32_insn_is_wide(u32 insn) +{ + return insn >= 0xe800; +} + +/* + * Macros/defines for extracting register numbers from instruction. + */ +u32 aarch32_insn_extract_reg_num(u32 insn, int offset) +{ + return (insn & (0xf << offset)) >> offset; +} + +#define OPC2_MASK 0x7 +#define OPC2_OFFSET 5 +u32 aarch32_insn_mcr_extract_opc2(u32 insn) +{ + return (insn & (OPC2_MASK << OPC2_OFFSET)) >> OPC2_OFFSET; +} + +#define CRM_MASK 0xf +u32 aarch32_insn_mcr_extract_crm(u32 insn) +{ + return insn & CRM_MASK; +} diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index d502a86bed9f..ef961ab8a224 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -80,7 +80,7 @@ unsigned int compat_elf_hwcap __read_mostly = COMPAT_ELF_HWCAP_DEFAULT; unsigned int compat_elf_hwcap2 __read_mostly; #endif -DECLARE_BITMAP(cpu_hwcaps, NCAPS); +DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS); static const char *cpu_name; phys_addr_t __fdt_pointer __initdata; diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c index 15dd021b0025..b6da20fa7a48 100644 --- a/arch/arm64/kernel/signal32.c +++ b/arch/arm64/kernel/signal32.c @@ -457,7 +457,7 @@ static void compat_setup_return(struct pt_regs *regs, struct k_sigaction *ka, { compat_ulong_t handler = ptr_to_compat(ka->sa.sa_handler); compat_ulong_t retcode; - compat_ulong_t spsr = regs->pstate & ~PSR_f; + compat_ulong_t spsr = regs->pstate & ~(PSR_f | COMPAT_PSR_E_BIT); int thumb; /* Check if the handler is written for ARM or Thumb */ @@ -471,6 +471,9 @@ static void compat_setup_return(struct pt_regs *regs, struct k_sigaction *ka, /* The IT state must be cleared for both ARM and Thumb-2 */ spsr &= ~COMPAT_PSR_IT_MASK; + /* Restore the original endianness */ + spsr |= COMPAT_PSR_ENDSTATE; + if (ka->sa.sa_flags & SA_RESTORER) { retcode = ptr_to_compat(ka->sa.sa_restorer); } else { diff --git a/arch/arm64/kernel/trace-events-emulation.h b/arch/arm64/kernel/trace-events-emulation.h new file mode 100644 index 000000000000..ae1dd598ea65 --- /dev/null +++ b/arch/arm64/kernel/trace-events-emulation.h @@ -0,0 +1,35 @@ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM emulation + +#if !defined(_TRACE_EMULATION_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_EMULATION_H + +#include <linux/tracepoint.h> + +TRACE_EVENT(instruction_emulation, + + TP_PROTO(const char *instr, u64 addr), + TP_ARGS(instr, addr), + + TP_STRUCT__entry( + __string(instr, instr) + __field(u64, addr) + ), + + TP_fast_assign( + __assign_str(instr, instr); + __entry->addr = addr; + ), + + TP_printk("instr=\"%s\" addr=0x%llx", __get_str(instr), __entry->addr) +); + +#endif /* _TRACE_EMULATION_H */ + +/* This part must be outside protection */ +#undef TRACE_INCLUDE_PATH +#undef TRACE_INCLUDE_FILE +#define TRACE_INCLUDE_PATH . + +#define TRACE_INCLUDE_FILE trace-events-emulation +#include <trace/define_trace.h> diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index de1b085e7963..0a801e3743d5 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -259,6 +259,69 @@ void arm64_notify_die(const char *str, struct pt_regs *regs, } } +static LIST_HEAD(undef_hook); +static DEFINE_RAW_SPINLOCK(undef_lock); + +void register_undef_hook(struct undef_hook *hook) +{ + unsigned long flags; + + raw_spin_lock_irqsave(&undef_lock, flags); + list_add(&hook->node, &undef_hook); + raw_spin_unlock_irqrestore(&undef_lock, flags); +} + +void unregister_undef_hook(struct undef_hook *hook) +{ + unsigned long flags; + + raw_spin_lock_irqsave(&undef_lock, flags); + list_del(&hook->node); + raw_spin_unlock_irqrestore(&undef_lock, flags); +} + +static int call_undef_hook(struct pt_regs *regs) +{ + struct undef_hook *hook; + unsigned long flags; + u32 instr; + int (*fn)(struct pt_regs *regs, u32 instr) = NULL; + void __user *pc = (void __user *)instruction_pointer(regs); + + if (!user_mode(regs)) + return 1; + + if (compat_thumb_mode(regs)) { + /* 16-bit Thumb instruction */ + if (get_user(instr, (u16 __user *)pc)) + goto exit; + instr = le16_to_cpu(instr); + if (aarch32_insn_is_wide(instr)) { + u32 instr2; + + if (get_user(instr2, (u16 __user *)(pc + 2))) + goto exit; + instr2 = le16_to_cpu(instr2); + instr = (instr << 16) | instr2; + } + } else { + /* 32-bit ARM instruction */ + if (get_user(instr, (u32 __user *)pc)) + goto exit; + instr = le32_to_cpu(instr); + } + + raw_spin_lock_irqsave(&undef_lock, flags); + list_for_each_entry(hook, &undef_hook, node) + if ((instr & hook->instr_mask) == hook->instr_val && + (regs->pstate & hook->pstate_mask) == hook->pstate_val) + fn = hook->fn; + + raw_spin_unlock_irqrestore(&undef_lock, flags); +exit: + return fn ? fn(regs, instr) : 1; +} + asmlinkage void __exception do_undefinstr(struct pt_regs *regs) { siginfo_t info; @@ -268,6 +331,9 @@ asmlinkage void __exception do_undefinstr(struct pt_regs *regs) if (!aarch32_break_handler(regs)) return; + if (call_undef_hook(regs) == 0) + return; + if (show_unhandled_signals && unhandled_signal(current, SIGILL) && printk_ratelimit()) { pr_info("%s[%d]: undefined instruction: pc=%p\n", diff --git a/arch/arm64/lib/clear_user.S b/arch/arm64/lib/clear_user.S index c17967fdf5f6..a9723c71c52b 100644 --- a/arch/arm64/lib/clear_user.S +++ b/arch/arm64/lib/clear_user.S @@ -16,7 +16,11 @@ * along with this program. If not, see <http://www.gnu.org/licenses/>. */ #include <linux/linkage.h> + +#include <asm/alternative.h> #include <asm/assembler.h> +#include <asm/cpufeature.h> +#include <asm/sysreg.h> .text @@ -29,6 +33,8 @@ * Alignment fixed up by hardware. */ ENTRY(__clear_user) +ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(0)), ARM64_HAS_PAN, \ + CONFIG_ARM64_PAN) mov x2, x1 // save the size for fixup return subs x1, x1, #8 b.mi 2f @@ -48,6 +54,8 @@ USER(9f, strh wzr, [x0], #2 ) b.mi 5f USER(9f, strb wzr, [x0] ) 5: mov x0, #0 +ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(1)), ARM64_HAS_PAN, \ + CONFIG_ARM64_PAN) ret ENDPROC(__clear_user) diff --git a/arch/arm64/lib/copy_from_user.S b/arch/arm64/lib/copy_from_user.S index 5e27add9d362..1be9ef27be97 100644 --- a/arch/arm64/lib/copy_from_user.S +++ b/arch/arm64/lib/copy_from_user.S @@ -15,7 +15,11 @@ */ #include <linux/linkage.h> + +#include <asm/alternative.h> #include <asm/assembler.h> +#include <asm/cpufeature.h> +#include <asm/sysreg.h> /* * Copy from user space to a kernel buffer (alignment handled by the hardware) @@ -28,14 +32,21 @@ * x0 - bytes not copied */ ENTRY(__copy_from_user) - add x4, x1, x2 // upper user buffer boundary - subs x2, x2, #8 +ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(0)), ARM64_HAS_PAN, \ + CONFIG_ARM64_PAN) + add x5, x1, x2 // upper user buffer boundary + subs x2, x2, #16 + b.mi 1f +0: +USER(9f, ldp x3, x4, [x1], #16) + subs x2, x2, #16 + stp x3, x4, [x0], #16 + b.pl 0b +1: adds x2, x2, #8 b.mi 2f -1: USER(9f, ldr x3, [x1], #8 ) - subs x2, x2, #8 + sub x2, x2, #8 str x3, [x0], #8 - b.pl 1b 2: adds x2, x2, #4 b.mi 3f USER(9f, ldr w3, [x1], #4 ) @@ -51,12 +62,14 @@ USER(9f, ldrh w3, [x1], #2 ) USER(9f, ldrb w3, [x1] ) strb w3, [x0] 5: mov x0, #0 +ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(1)), ARM64_HAS_PAN, \ + CONFIG_ARM64_PAN) ret ENDPROC(__copy_from_user) .section .fixup,"ax" .align 2 -9: sub x2, x4, x1 +9: sub x2, x5, x1 mov x3, x2 10: strb wzr, [x0], #1 // zero remaining buffer space subs x3, x3, #1 diff --git a/arch/arm64/lib/copy_in_user.S b/arch/arm64/lib/copy_in_user.S index 84b6c9bb9b93..1b94661e22b3 100644 --- a/arch/arm64/lib/copy_in_user.S +++ b/arch/arm64/lib/copy_in_user.S @@ -17,7 +17,11 @@ */ #include <linux/linkage.h> + +#include <asm/alternative.h> #include <asm/assembler.h> +#include <asm/cpufeature.h> +#include <asm/sysreg.h> /* * Copy from user space to user space (alignment handled by the hardware) @@ -30,14 +34,21 @@ * x0 - bytes not copied */ ENTRY(__copy_in_user) - add x4, x0, x2 // upper user buffer boundary - subs x2, x2, #8 +ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(0)), ARM64_HAS_PAN, \ + CONFIG_ARM64_PAN) + add x5, x0, x2 // upper user buffer boundary + subs x2, x2, #16 + b.mi 1f +0: +USER(9f, ldp x3, x4, [x1], #16) + subs x2, x2, #16 +USER(9f, stp x3, x4, [x0], #16) + b.pl 0b +1: adds x2, x2, #8 b.mi 2f -1: USER(9f, ldr x3, [x1], #8 ) - subs x2, x2, #8 + sub x2, x2, #8 USER(9f, str x3, [x0], #8 ) - b.pl 1b 2: adds x2, x2, #4 b.mi 3f USER(9f, ldr w3, [x1], #4 ) @@ -53,11 +64,13 @@ USER(9f, strh w3, [x0], #2 ) USER(9f, ldrb w3, [x1] ) USER(9f, strb w3, [x0] ) 5: mov x0, #0 +ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(1)), ARM64_HAS_PAN, \ + CONFIG_ARM64_PAN) ret ENDPROC(__copy_in_user) .section .fixup,"ax" .align 2 -9: sub x0, x4, x0 // bytes not copied +9: sub x0, x5, x0 // bytes not copied ret .previous diff --git a/arch/arm64/lib/copy_to_user.S b/arch/arm64/lib/copy_to_user.S index a0aeeb9b7a28..a257b47e2dc4 100644 --- a/arch/arm64/lib/copy_to_user.S +++ b/arch/arm64/lib/copy_to_user.S @@ -15,7 +15,11 @@ */ #include <linux/linkage.h> + +#include <asm/alternative.h> #include <asm/assembler.h> +#include <asm/cpufeature.h> +#include <asm/sysreg.h> /* * Copy to user space from a kernel buffer (alignment handled by the hardware) @@ -28,14 +32,21 @@ * x0 - bytes not copied */ ENTRY(__copy_to_user) - add x4, x0, x2 // upper user buffer boundary - subs x2, x2, #8 +ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(0)), ARM64_HAS_PAN, \ + CONFIG_ARM64_PAN) + add x5, x0, x2 // upper user buffer boundary + subs x2, x2, #16 + b.mi 1f +0: + ldp x3, x4, [x1], #16 + subs x2, x2, #16 +USER(9f, stp x3, x4, [x0], #16) + b.pl 0b +1: adds x2, x2, #8 b.mi 2f -1: ldr x3, [x1], #8 - subs x2, x2, #8 + sub x2, x2, #8 USER(9f, str x3, [x0], #8 ) - b.pl 1b 2: adds x2, x2, #4 b.mi 3f ldr w3, [x1], #4 @@ -51,11 +62,13 @@ USER(9f, strh w3, [x0], #2 ) ldrb w3, [x1] USER(9f, strb w3, [x0] ) 5: mov x0, #0 +ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(1)), ARM64_HAS_PAN, \ + CONFIG_ARM64_PAN) ret ENDPROC(__copy_to_user) .section .fixup,"ax" .align 2 -9: sub x0, x4, x0 // bytes not copied +9: sub x0, x5, x0 // bytes not copied ret .previous diff --git a/arch/arm64/mm/cache.S b/arch/arm64/mm/cache.S index 8eaf18577d71..de1e66bccd0c 100644 --- a/arch/arm64/mm/cache.S +++ b/arch/arm64/mm/cache.S @@ -21,7 +21,7 @@ #include <linux/init.h> #include <asm/assembler.h> #include <asm/cpufeature.h> -#include <asm/alternative-asm.h> +#include <asm/alternative.h> #include "proc-macros.S" diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 6094c64b3380..71e5707ac7f4 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -30,9 +30,11 @@ #include <linux/highmem.h> #include <linux/perf_event.h> +#include <asm/cpufeature.h> #include <asm/exception.h> #include <asm/debug-monitors.h> #include <asm/esr.h> +#include <asm/sysreg.h> #include <asm/system_misc.h> #include <asm/pgtable.h> #include <asm/tlbflush.h> @@ -225,6 +227,13 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, } /* + * PAN bit set implies the fault happened in kernel space, but not + * in the arch's user access functions. + */ + if (IS_ENABLED(CONFIG_ARM64_PAN) && (regs->pstate & PSR_PAN_BIT)) + goto no_context; + + /* * As per x86, we may deadlock here. However, since the kernel only * validly references user space from well defined areas of the code, * we can bug out early if this is from code which shouldn't. @@ -531,3 +540,10 @@ asmlinkage int __exception do_debug_exception(unsigned long addr, return 0; } + +#ifdef CONFIG_ARM64_PAN +void cpu_enable_pan(void) +{ + config_sctlr_el1(SCTLR_EL1_SPAN, 0); +} +#endif /* CONFIG_ARM64_PAN */ |