diff options
Diffstat (limited to 'arch/arm64/kernel/process.c')
| -rw-r--r-- | arch/arm64/kernel/process.c | 100 |
1 files changed, 88 insertions, 12 deletions
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 4ae31b7af6c3..3e7c8c8195c3 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -43,6 +43,7 @@ #include <linux/stacktrace.h> #include <asm/alternative.h> +#include <asm/arch_timer.h> #include <asm/compat.h> #include <asm/cpufeature.h> #include <asm/cacheflush.h> @@ -271,12 +272,21 @@ static void flush_tagged_addr_state(void) clear_thread_flag(TIF_TAGGED_ADDR); } +static void flush_poe(void) +{ + if (!system_supports_poe()) + return; + + write_sysreg_s(POR_EL0_INIT, SYS_POR_EL0); +} + void flush_thread(void) { fpsimd_flush_thread(); tls_thread_flush(); flush_ptrace_hw_breakpoint(current); flush_tagged_addr_state(); + flush_poe(); } void arch_release_task_struct(struct task_struct *tsk) @@ -371,6 +381,9 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) if (system_supports_tpidr2()) p->thread.tpidr2_el0 = read_sysreg_s(SYS_TPIDR2_EL0); + if (system_supports_poe()) + p->thread.por_el0 = read_sysreg_s(SYS_POR_EL0); + if (stack_start) { if (is_compat_thread(task_thread_info(p))) childregs->compat_sp = stack_start; @@ -399,6 +412,9 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) p->thread.cpu_context.x19 = (unsigned long)args->fn; p->thread.cpu_context.x20 = (unsigned long)args->fn_arg; + + if (system_supports_poe()) + p->thread.por_el0 = POR_EL0_INIT; } p->thread.cpu_context.pc = (unsigned long)ret_from_fork; p->thread.cpu_context.sp = (unsigned long)childregs; @@ -472,27 +488,63 @@ static void entry_task_switch(struct task_struct *next) } /* - * ARM erratum 1418040 handling, affecting the 32bit view of CNTVCT. - * Ensure access is disabled when switching to a 32bit task, ensure - * access is enabled when switching to a 64bit task. + * Handle sysreg updates for ARM erratum 1418040 which affects the 32bit view of + * CNTVCT, various other errata which require trapping all CNTVCT{,_EL0} + * accesses and prctl(PR_SET_TSC). Ensure access is disabled iff a workaround is + * required or PR_TSC_SIGSEGV is set. */ -static void erratum_1418040_thread_switch(struct task_struct *next) +static void update_cntkctl_el1(struct task_struct *next) { - if (!IS_ENABLED(CONFIG_ARM64_ERRATUM_1418040) || - !this_cpu_has_cap(ARM64_WORKAROUND_1418040)) - return; + struct thread_info *ti = task_thread_info(next); - if (is_compat_thread(task_thread_info(next))) + if (test_ti_thread_flag(ti, TIF_TSC_SIGSEGV) || + has_erratum_handler(read_cntvct_el0) || + (IS_ENABLED(CONFIG_ARM64_ERRATUM_1418040) && + this_cpu_has_cap(ARM64_WORKAROUND_1418040) && + is_compat_thread(ti))) sysreg_clear_set(cntkctl_el1, ARCH_TIMER_USR_VCT_ACCESS_EN, 0); else sysreg_clear_set(cntkctl_el1, 0, ARCH_TIMER_USR_VCT_ACCESS_EN); } -static void erratum_1418040_new_exec(void) +static void cntkctl_thread_switch(struct task_struct *prev, + struct task_struct *next) { + if ((read_ti_thread_flags(task_thread_info(prev)) & + (_TIF_32BIT | _TIF_TSC_SIGSEGV)) != + (read_ti_thread_flags(task_thread_info(next)) & + (_TIF_32BIT | _TIF_TSC_SIGSEGV))) + update_cntkctl_el1(next); +} + +static int do_set_tsc_mode(unsigned int val) +{ + bool tsc_sigsegv; + + if (val == PR_TSC_SIGSEGV) + tsc_sigsegv = true; + else if (val == PR_TSC_ENABLE) + tsc_sigsegv = false; + else + return -EINVAL; + preempt_disable(); - erratum_1418040_thread_switch(current); + update_thread_flag(TIF_TSC_SIGSEGV, tsc_sigsegv); + update_cntkctl_el1(current); preempt_enable(); + + return 0; +} + +static void permission_overlay_switch(struct task_struct *next) +{ + if (!system_supports_poe()) + return; + + current->thread.por_el0 = read_sysreg_s(SYS_POR_EL0); + if (current->thread.por_el0 != next->thread.por_el0) { + write_sysreg_s(next->thread.por_el0, SYS_POR_EL0); + } } /* @@ -528,8 +580,9 @@ struct task_struct *__switch_to(struct task_struct *prev, contextidr_thread_switch(next); entry_task_switch(next); ssbs_thread_switch(next); - erratum_1418040_thread_switch(next); + cntkctl_thread_switch(prev, next); ptrauth_thread_switch_user(next); + permission_overlay_switch(next); /* * Complete any pending TLB or cache maintenance on this CPU in case @@ -645,7 +698,7 @@ void arch_setup_new_exec(void) current->mm->context.flags = mmflags; ptrauth_thread_init_user(); mte_thread_init_user(); - erratum_1418040_new_exec(); + do_set_tsc_mode(PR_TSC_ENABLE); if (task_spec_ssb_noexec(current)) { arch_prctl_spec_ctrl_set(current, PR_SPEC_STORE_BYPASS, @@ -754,3 +807,26 @@ int arch_elf_adjust_prot(int prot, const struct arch_elf_state *state, return prot; } #endif + +int get_tsc_mode(unsigned long adr) +{ + unsigned int val; + + if (is_compat_task()) + return -EINVAL; + + if (test_thread_flag(TIF_TSC_SIGSEGV)) + val = PR_TSC_SIGSEGV; + else + val = PR_TSC_ENABLE; + + return put_user(val, (unsigned int __user *)adr); +} + +int set_tsc_mode(unsigned int val) +{ + if (is_compat_task()) + return -EINVAL; + + return do_set_tsc_mode(val); +} |