diff options
| -rw-r--r-- | Documentation/arm64/legacy_instructions.txt | 12 | ||||
| -rw-r--r-- | arch/arm64/Kconfig | 15 | ||||
| -rw-r--r-- | arch/arm64/include/asm/cputype.h | 1 | ||||
| -rw-r--r-- | arch/arm64/include/asm/ptrace.h | 7 | ||||
| -rw-r--r-- | arch/arm64/kernel/armv8_deprecated.c | 80 | ||||
| -rw-r--r-- | arch/arm64/kernel/signal32.c | 5 |
6 files changed, 119 insertions, 1 deletions
diff --git a/Documentation/arm64/legacy_instructions.txt b/Documentation/arm64/legacy_instructions.txt index a3b3da2ec6ed..01bf3d9fac85 100644 --- a/Documentation/arm64/legacy_instructions.txt +++ b/Documentation/arm64/legacy_instructions.txt @@ -32,6 +32,9 @@ 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} @@ -43,3 +46,12 @@ Default: Undef (0) 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 b1f9a20a3677..21a59bf37145 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -540,6 +540,21 @@ config CP15_BARRIER_EMULATION 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 diff --git a/arch/arm64/include/asm/cputype.h b/arch/arm64/include/asm/cputype.h index 68732e9a02fb..a84ec605bed8 100644 --- a/arch/arm64/include/asm/cputype.h +++ b/arch/arm64/include/asm/cputype.h @@ -82,6 +82,7 @@ (((mmfr0) & ID_AA64MMFR0_BIGEND_MASK) >> ID_AA64MMFR0_BIGEND_SHIFT) #define SCTLR_EL1_CP15BEN (0x1 << 5) +#define SCTLR_EL1_SED (0x1 << 8) #ifndef __ASSEMBLY__ 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/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c index 68b955e1fd99..7922c2e710ca 100644 --- a/arch/arm64/kernel/armv8_deprecated.c +++ b/arch/arm64/kernel/armv8_deprecated.c @@ -548,6 +548,79 @@ static struct insn_emulation_ops cp15_barrier_ops = { .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) { @@ -573,6 +646,13 @@ static int __init armv8_deprecated_init(void) 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); diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c index 192d900c058f..e299de396e9b 100644 --- a/arch/arm64/kernel/signal32.c +++ b/arch/arm64/kernel/signal32.c @@ -440,7 +440,7 @@ 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 */ @@ -454,6 +454,9 @@ 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 { |