diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/include/asm/elf.h | 13 | ||||
| -rw-r--r-- | arch/arm64/include/asm/processor.h | 5 | ||||
| -rw-r--r-- | arch/arm64/include/uapi/asm/auxvec.h | 3 | ||||
| -rw-r--r-- | arch/arm64/kernel/cpufeature.c | 1 | ||||
| -rw-r--r-- | arch/arm64/kernel/signal.c | 52 |
5 files changed, 66 insertions, 8 deletions
diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h index fac1c4de7898..433b9554c6a1 100644 --- a/arch/arm64/include/asm/elf.h +++ b/arch/arm64/include/asm/elf.h @@ -121,6 +121,9 @@ #ifndef __ASSEMBLY__ +#include <linux/bug.h> +#include <asm/processor.h> /* for signal_minsigstksz, used by ARCH_DLINFO */ + typedef unsigned long elf_greg_t; #define ELF_NGREG (sizeof(struct user_pt_regs) / sizeof(elf_greg_t)) @@ -148,6 +151,16 @@ typedef struct user_fpsimd_state elf_fpregset_t; do { \ NEW_AUX_ENT(AT_SYSINFO_EHDR, \ (elf_addr_t)current->mm->context.vdso); \ + \ + /* \ + * Should always be nonzero unless there's a kernel bug. \ + * If we haven't determined a sensible value to give to \ + * userspace, omit the entry: \ + */ \ + if (likely(signal_minsigstksz)) \ + NEW_AUX_ENT(AT_MINSIGSTKSZ, signal_minsigstksz); \ + else \ + NEW_AUX_ENT(AT_IGNORE, 0); \ } while (0) #define ARCH_HAS_SETUP_ADDITIONAL_PAGES diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index 767598932549..65ab83e8926e 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -35,6 +35,8 @@ #ifdef __KERNEL__ #include <linux/build_bug.h> +#include <linux/cache.h> +#include <linux/init.h> #include <linux/stddef.h> #include <linux/string.h> @@ -244,6 +246,9 @@ void cpu_enable_pan(const struct arm64_cpu_capabilities *__unused); void cpu_enable_cache_maint_trap(const struct arm64_cpu_capabilities *__unused); void cpu_clear_disr(const struct arm64_cpu_capabilities *__unused); +extern unsigned long __ro_after_init signal_minsigstksz; /* sigframe size */ +extern void __init minsigstksz_setup(void); + /* Userspace interface for PR_SVE_{SET,GET}_VL prctl()s: */ #define SVE_SET_VL(arg) sve_set_current_vl(arg) #define SVE_GET_VL() sve_get_current_vl() diff --git a/arch/arm64/include/uapi/asm/auxvec.h b/arch/arm64/include/uapi/asm/auxvec.h index ec0a86d484e1..743c0b84fd30 100644 --- a/arch/arm64/include/uapi/asm/auxvec.h +++ b/arch/arm64/include/uapi/asm/auxvec.h @@ -19,7 +19,8 @@ /* vDSO location */ #define AT_SYSINFO_EHDR 33 +#define AT_MINSIGSTKSZ 51 /* stack needed for signal delivery */ -#define AT_VECTOR_SIZE_ARCH 1 /* entries in ARCH_DLINFO */ +#define AT_VECTOR_SIZE_ARCH 2 /* entries in ARCH_DLINFO */ #endif diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index fbee8c17a4e6..d2856b129097 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1618,6 +1618,7 @@ void __init setup_cpu_features(void) pr_info("emulated: Privileged Access Never (PAN) using TTBR0_EL1 switching\n"); sve_setup(); + minsigstksz_setup(); /* Advertise that we have computed the system capabilities */ set_sys_caps_initialised(); diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 154b7d30145d..e7da5dba7ba8 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -17,6 +17,7 @@ * along with this program. If not, see <http://www.gnu.org/licenses/>. */ +#include <linux/cache.h> #include <linux/compat.h> #include <linux/errno.h> #include <linux/kernel.h> @@ -570,8 +571,15 @@ badframe: return 0; } -/* Determine the layout of optional records in the signal frame */ -static int setup_sigframe_layout(struct rt_sigframe_user_layout *user) +/* + * Determine the layout of optional records in the signal frame + * + * add_all: if true, lays out the biggest possible signal frame for + * this task; otherwise, generates a layout for the current state + * of the task. + */ +static int setup_sigframe_layout(struct rt_sigframe_user_layout *user, + bool add_all) { int err; @@ -581,7 +589,7 @@ static int setup_sigframe_layout(struct rt_sigframe_user_layout *user) return err; /* fault information, if valid */ - if (current->thread.fault_code) { + if (add_all || current->thread.fault_code) { err = sigframe_alloc(user, &user->esr_offset, sizeof(struct esr_context)); if (err) @@ -591,8 +599,14 @@ static int setup_sigframe_layout(struct rt_sigframe_user_layout *user) if (system_supports_sve()) { unsigned int vq = 0; - if (test_thread_flag(TIF_SVE)) - vq = sve_vq_from_vl(current->thread.sve_vl); + if (add_all || test_thread_flag(TIF_SVE)) { + int vl = sve_max_vl; + + if (!add_all) + vl = current->thread.sve_vl; + + vq = sve_vq_from_vl(vl); + } err = sigframe_alloc(user, &user->sve_offset, SVE_SIG_CONTEXT_SIZE(vq)); @@ -603,7 +617,6 @@ static int setup_sigframe_layout(struct rt_sigframe_user_layout *user) return sigframe_alloc_end(user); } - static int setup_sigframe(struct rt_sigframe_user_layout *user, struct pt_regs *regs, sigset_t *set) { @@ -701,7 +714,7 @@ static int get_sigframe(struct rt_sigframe_user_layout *user, int err; init_user_layout(user); - err = setup_sigframe_layout(user); + err = setup_sigframe_layout(user, false); if (err) return err; @@ -936,3 +949,28 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, thread_flags = READ_ONCE(current_thread_info()->flags); } while (thread_flags & _TIF_WORK_MASK); } + +unsigned long __ro_after_init signal_minsigstksz; + +/* + * Determine the stack space required for guaranteed signal devliery. + * This function is used to populate AT_MINSIGSTKSZ at process startup. + * cpufeatures setup is assumed to be complete. + */ +void __init minsigstksz_setup(void) +{ + struct rt_sigframe_user_layout user; + + init_user_layout(&user); + + /* + * If this fails, SIGFRAME_MAXSZ needs to be enlarged. It won't + * be big enough, but it's our best guess: + */ + if (WARN_ON(setup_sigframe_layout(&user, true))) + return; + + signal_minsigstksz = sigframe_size(&user) + + round_up(sizeof(struct frame_record), 16) + + 16; /* max alignment padding */ +} |