From a45cedaa1ac0da7b30882afb42ff9d5285e9bb44 Mon Sep 17 00:00:00 2001 From: Andy Chiu Date: Mon, 5 Jun 2023 11:07:10 +0000 Subject: riscv: signal: check fp-reserved words unconditionally In order to let kernel/user locate and identify an extension context on the existing sigframe, we are going to utilize reserved space of fp and encode the information there. And since the sigcontext has already preserved a space for fp context w or w/o CONFIG_FPU, we move those reserved words checking/setting routine back into generic code. This commit also undone an additional logical change carried by the refactor commit 007f5c3589578 ("Refactor FPU code in signal setup/return procedures"). Originally we did not restore fp context if restoring of gpr have failed. And it was fine on the other side. In such way the kernel could keep the regfiles intact, and potentially react at the failing point of restore. Signed-off-by: Andy Chiu Acked-by: Conor Dooley Acked-by: Heiko Stuebner Tested-by: Heiko Stuebner Link: https://lore.kernel.org/r/20230605110724.21391-14-andy.chiu@sifive.com Signed-off-by: Palmer Dabbelt --- arch/riscv/kernel/signal.c | 55 +++++++++++++++++++++++----------------------- 1 file changed, 28 insertions(+), 27 deletions(-) (limited to 'arch/riscv/kernel/signal.c') diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c index 9aff9d720590..6b4a5c90bd87 100644 --- a/arch/riscv/kernel/signal.c +++ b/arch/riscv/kernel/signal.c @@ -40,26 +40,13 @@ static long restore_fp_state(struct pt_regs *regs, { long err; struct __riscv_d_ext_state __user *state = &sc_fpregs->d; - size_t i; err = __copy_from_user(¤t->thread.fstate, state, sizeof(*state)); if (unlikely(err)) return err; fstate_restore(current, regs); - - /* We support no other extension state at this time. */ - for (i = 0; i < ARRAY_SIZE(sc_fpregs->q.reserved); i++) { - u32 value; - - err = __get_user(value, &sc_fpregs->q.reserved[i]); - if (unlikely(err)) - break; - if (value != 0) - return -EINVAL; - } - - return err; + return 0; } static long save_fp_state(struct pt_regs *regs, @@ -67,20 +54,9 @@ static long save_fp_state(struct pt_regs *regs, { long err; struct __riscv_d_ext_state __user *state = &sc_fpregs->d; - size_t i; fstate_save(current, regs); err = __copy_to_user(state, ¤t->thread.fstate, sizeof(*state)); - if (unlikely(err)) - return err; - - /* We support no other extension state at this time. */ - for (i = 0; i < ARRAY_SIZE(sc_fpregs->q.reserved); i++) { - err = __put_user(0, &sc_fpregs->q.reserved[i]); - if (unlikely(err)) - break; - } - return err; } #else @@ -92,11 +68,30 @@ static long restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) { long err; + size_t i; + /* sc_regs is structured the same as the start of pt_regs */ err = __copy_from_user(regs, &sc->sc_regs, sizeof(sc->sc_regs)); + if (unlikely(err)) + return err; + /* Restore the floating-point state. */ - if (has_fpu()) - err |= restore_fp_state(regs, &sc->sc_fpregs); + if (has_fpu()) { + err = restore_fp_state(regs, &sc->sc_fpregs); + if (unlikely(err)) + return err; + } + + /* We support no other extension state at this time. */ + for (i = 0; i < ARRAY_SIZE(sc->sc_fpregs.q.reserved); i++) { + u32 value; + + err = __get_user(value, &sc->sc_fpregs.q.reserved[i]); + if (unlikely(err)) + break; + if (value != 0) + return -EINVAL; + } return err; } @@ -147,11 +142,17 @@ static long setup_sigcontext(struct rt_sigframe __user *frame, { struct sigcontext __user *sc = &frame->uc.uc_mcontext; long err; + size_t i; + /* sc_regs is structured the same as the start of pt_regs */ err = __copy_to_user(&sc->sc_regs, regs, sizeof(sc->sc_regs)); /* Save the floating-point state. */ if (has_fpu()) err |= save_fp_state(regs, &sc->sc_fpregs); + /* We support no other extension state at this time. */ + for (i = 0; i < ARRAY_SIZE(sc->sc_fpregs.q.reserved); i++) + err |= __put_user(0, &sc->sc_fpregs.q.reserved[i]); + return err; } -- cgit v1.2.3 From 8ee0b41898fa26f66e32237f179b6989c65600d6 Mon Sep 17 00:00:00 2001 From: Greentime Hu Date: Mon, 5 Jun 2023 11:07:11 +0000 Subject: riscv: signal: Add sigcontext save/restore for vector This patch facilitates the existing fp-reserved words for placement of the first extension's context header on the user's sigframe. A context header consists of a distinct magic word and the size, including the header itself, of an extension on the stack. Then, the frame is followed by the context of that extension, and then a header + context body for another extension if exists. If there is no more extension to come, then the frame must be ended with a null context header. A special case is rv64gc, where the kernel support no extensions requiring to expose additional regfile to the user. In such case the kernel would place the null context header right after the first reserved word of __riscv_q_ext_state when saving sigframe. And the kernel would check if all reserved words are zeros when a signal handler returns. __riscv_q_ext_state---->| |<-__riscv_extra_ext_header ~ ~ .reserved[0]--->|0 |<- .reserved <-------|magic |<- .hdr | |size |_______ end of sc_fpregs | |ext-bdy| | ~ ~ +)size ------->|magic |<- another context header |size | |ext-bdy| ~ ~ |magic:0|<- null context header |size:0 | The vector registers will be saved in datap pointer. The datap pointer will be allocated dynamically when the task needs in kernel space. On the other hand, datap pointer on the sigframe will be set right after the __riscv_v_ext_state data structure. Co-developed-by: Vincent Chen Signed-off-by: Vincent Chen Signed-off-by: Greentime Hu Suggested-by: Vineet Gupta Suggested-by: Richard Henderson Co-developed-by: Andy Chiu Signed-off-by: Andy Chiu Acked-by: Conor Dooley Acked-by: Heiko Stuebner Tested-by: Heiko Stuebner Link: https://lore.kernel.org/r/20230605110724.21391-15-andy.chiu@sifive.com Signed-off-by: Palmer Dabbelt --- arch/riscv/include/uapi/asm/ptrace.h | 15 +++ arch/riscv/include/uapi/asm/sigcontext.h | 16 ++- arch/riscv/kernel/setup.c | 3 + arch/riscv/kernel/signal.c | 174 ++++++++++++++++++++++++++++--- 4 files changed, 193 insertions(+), 15 deletions(-) (limited to 'arch/riscv/kernel/signal.c') diff --git a/arch/riscv/include/uapi/asm/ptrace.h b/arch/riscv/include/uapi/asm/ptrace.h index e8d127ec5cf7..e17c550986a6 100644 --- a/arch/riscv/include/uapi/asm/ptrace.h +++ b/arch/riscv/include/uapi/asm/ptrace.h @@ -71,6 +71,21 @@ struct __riscv_q_ext_state { __u32 reserved[3]; }; +struct __riscv_ctx_hdr { + __u32 magic; + __u32 size; +}; + +struct __riscv_extra_ext_header { + __u32 __padding[129] __attribute__((aligned(16))); + /* + * Reserved for expansion of sigcontext structure. Currently zeroed + * upon signal, and must be zero upon sigreturn. + */ + __u32 reserved; + struct __riscv_ctx_hdr hdr; +}; + union __riscv_fp_state { struct __riscv_f_ext_state f; struct __riscv_d_ext_state d; diff --git a/arch/riscv/include/uapi/asm/sigcontext.h b/arch/riscv/include/uapi/asm/sigcontext.h index 84f2dfcfdbce..8b8a8541673a 100644 --- a/arch/riscv/include/uapi/asm/sigcontext.h +++ b/arch/riscv/include/uapi/asm/sigcontext.h @@ -8,6 +8,17 @@ #include +/* The Magic number for signal context frame header. */ +#define RISCV_V_MAGIC 0x53465457 +#define END_MAGIC 0x0 + +/* The size of END signal context header. */ +#define END_HDR_SIZE 0x0 + +struct __sc_riscv_v_state { + struct __riscv_v_ext_state v_state; +} __attribute__((aligned(16))); + /* * Signal context structure * @@ -16,7 +27,10 @@ */ struct sigcontext { struct user_regs_struct sc_regs; - union __riscv_fp_state sc_fpregs; + union { + union __riscv_fp_state sc_fpregs; + struct __riscv_extra_ext_header sc_extdesc; + }; }; #endif /* _UAPI_ASM_RISCV_SIGCONTEXT_H */ diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c index 36b026057503..60ebe757ef20 100644 --- a/arch/riscv/kernel/setup.c +++ b/arch/riscv/kernel/setup.c @@ -262,6 +262,8 @@ static void __init parse_dtb(void) #endif } +extern void __init init_rt_signal_env(void); + void __init setup_arch(char **cmdline_p) { parse_dtb(); @@ -295,6 +297,7 @@ void __init setup_arch(char **cmdline_p) riscv_init_cbo_blocksizes(); riscv_fill_hwcap(); + init_rt_signal_env(); apply_boot_alternatives(); if (IS_ENABLED(CONFIG_RISCV_ISA_ZICBOM) && riscv_isa_extension_available(NULL, ZICBOM)) diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c index 6b4a5c90bd87..c46f3dc039bb 100644 --- a/arch/riscv/kernel/signal.c +++ b/arch/riscv/kernel/signal.c @@ -19,10 +19,12 @@ #include #include #include +#include #include #include extern u32 __user_rt_sigreturn[2]; +static size_t riscv_v_sc_size __ro_after_init; #define DEBUG_SIG 0 @@ -64,12 +66,87 @@ static long save_fp_state(struct pt_regs *regs, #define restore_fp_state(task, regs) (0) #endif +#ifdef CONFIG_RISCV_ISA_V + +static long save_v_state(struct pt_regs *regs, void __user **sc_vec) +{ + struct __riscv_ctx_hdr __user *hdr; + struct __sc_riscv_v_state __user *state; + void __user *datap; + long err; + + hdr = *sc_vec; + /* Place state to the user's signal context space after the hdr */ + state = (struct __sc_riscv_v_state __user *)(hdr + 1); + /* Point datap right after the end of __sc_riscv_v_state */ + datap = state + 1; + + /* datap is designed to be 16 byte aligned for better performance */ + WARN_ON(unlikely(!IS_ALIGNED((unsigned long)datap, 16))); + + riscv_v_vstate_save(current, regs); + /* Copy everything of vstate but datap. */ + err = __copy_to_user(&state->v_state, ¤t->thread.vstate, + offsetof(struct __riscv_v_ext_state, datap)); + /* Copy the pointer datap itself. */ + err |= __put_user(datap, &state->v_state.datap); + /* Copy the whole vector content to user space datap. */ + err |= __copy_to_user(datap, current->thread.vstate.datap, riscv_v_vsize); + /* Copy magic to the user space after saving all vector conetext */ + err |= __put_user(RISCV_V_MAGIC, &hdr->magic); + err |= __put_user(riscv_v_sc_size, &hdr->size); + if (unlikely(err)) + return err; + + /* Only progress the sv_vec if everything has done successfully */ + *sc_vec += riscv_v_sc_size; + return 0; +} + +/* + * Restore Vector extension context from the user's signal frame. This function + * assumes a valid extension header. So magic and size checking must be done by + * the caller. + */ +static long __restore_v_state(struct pt_regs *regs, void __user *sc_vec) +{ + long err; + struct __sc_riscv_v_state __user *state = sc_vec; + void __user *datap; + + /* Copy everything of __sc_riscv_v_state except datap. */ + err = __copy_from_user(¤t->thread.vstate, &state->v_state, + offsetof(struct __riscv_v_ext_state, datap)); + if (unlikely(err)) + return err; + + /* Copy the pointer datap itself. */ + err = __get_user(datap, &state->v_state.datap); + if (unlikely(err)) + return err; + /* + * Copy the whole vector content from user space datap. Use + * copy_from_user to prevent information leak. + */ + err = copy_from_user(current->thread.vstate.datap, datap, riscv_v_vsize); + if (unlikely(err)) + return err; + + riscv_v_vstate_restore(current, regs); + + return err; +} +#else +#define save_v_state(task, regs) (0) +#define __restore_v_state(task, regs) (0) +#endif + static long restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) { + void __user *sc_ext_ptr = &sc->sc_extdesc.hdr; + __u32 rsvd; long err; - size_t i; - /* sc_regs is structured the same as the start of pt_regs */ err = __copy_from_user(regs, &sc->sc_regs, sizeof(sc->sc_regs)); if (unlikely(err)) @@ -82,32 +159,81 @@ static long restore_sigcontext(struct pt_regs *regs, return err; } - /* We support no other extension state at this time. */ - for (i = 0; i < ARRAY_SIZE(sc->sc_fpregs.q.reserved); i++) { - u32 value; + /* Check the reserved word before extensions parsing */ + err = __get_user(rsvd, &sc->sc_extdesc.reserved); + if (unlikely(err)) + return err; + if (unlikely(rsvd)) + return -EINVAL; + + while (!err) { + __u32 magic, size; + struct __riscv_ctx_hdr __user *head = sc_ext_ptr; - err = __get_user(value, &sc->sc_fpregs.q.reserved[i]); + err |= __get_user(magic, &head->magic); + err |= __get_user(size, &head->size); if (unlikely(err)) + return err; + + sc_ext_ptr += sizeof(*head); + switch (magic) { + case END_MAGIC: + if (size != END_HDR_SIZE) + return -EINVAL; + + return 0; + case RISCV_V_MAGIC: + if (!has_vector() || !riscv_v_vstate_query(regs) || + size != riscv_v_sc_size) + return -EINVAL; + + err = __restore_v_state(regs, sc_ext_ptr); break; - if (value != 0) + default: return -EINVAL; + } + sc_ext_ptr = (void __user *)head + size; } return err; } +static size_t get_rt_frame_size(void) +{ + struct rt_sigframe __user *frame; + size_t frame_size; + size_t total_context_size = 0; + + frame_size = sizeof(*frame); + + if (has_vector() && riscv_v_vstate_query(task_pt_regs(current))) + total_context_size += riscv_v_sc_size; + /* + * Preserved a __riscv_ctx_hdr for END signal context header if an + * extension uses __riscv_extra_ext_header + */ + if (total_context_size) + total_context_size += sizeof(struct __riscv_ctx_hdr); + + frame_size += total_context_size; + + frame_size = round_up(frame_size, 16); + return frame_size; +} + SYSCALL_DEFINE0(rt_sigreturn) { struct pt_regs *regs = current_pt_regs(); struct rt_sigframe __user *frame; struct task_struct *task; sigset_t set; + size_t frame_size = get_rt_frame_size(); /* Always make any pending restarted system calls return -EINTR */ current->restart_block.fn = do_no_restart_syscall; frame = (struct rt_sigframe __user *)regs->sp; - if (!access_ok(frame, sizeof(*frame))) + if (!access_ok(frame, frame_size)) goto badframe; if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) @@ -141,17 +267,22 @@ static long setup_sigcontext(struct rt_sigframe __user *frame, struct pt_regs *regs) { struct sigcontext __user *sc = &frame->uc.uc_mcontext; + struct __riscv_ctx_hdr __user *sc_ext_ptr = &sc->sc_extdesc.hdr; long err; - size_t i; /* sc_regs is structured the same as the start of pt_regs */ err = __copy_to_user(&sc->sc_regs, regs, sizeof(sc->sc_regs)); /* Save the floating-point state. */ if (has_fpu()) err |= save_fp_state(regs, &sc->sc_fpregs); - /* We support no other extension state at this time. */ - for (i = 0; i < ARRAY_SIZE(sc->sc_fpregs.q.reserved); i++) - err |= __put_user(0, &sc->sc_fpregs.q.reserved[i]); + /* Save the vector state. */ + if (has_vector() && riscv_v_vstate_query(regs)) + err |= save_v_state(regs, (void __user **)&sc_ext_ptr); + /* Write zero to fp-reserved space and check it on restore_sigcontext */ + err |= __put_user(0, &sc->sc_extdesc.reserved); + /* And put END __riscv_ctx_hdr at the end. */ + err |= __put_user(END_MAGIC, &sc_ext_ptr->magic); + err |= __put_user(END_HDR_SIZE, &sc_ext_ptr->size); return err; } @@ -176,6 +307,13 @@ static inline void __user *get_sigframe(struct ksignal *ksig, /* Align the stack frame. */ sp &= ~0xfUL; + /* + * Fail if the size of the altstack is not large enough for the + * sigframe construction. + */ + if (current->sas_ss_size && sp < current->sas_ss_sp) + return (void __user __force *)-1UL; + return (void __user *)sp; } @@ -185,9 +323,10 @@ static int setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct rt_sigframe __user *frame; long err = 0; unsigned long __maybe_unused addr; + size_t frame_size = get_rt_frame_size(); - frame = get_sigframe(ksig, regs, sizeof(*frame)); - if (!access_ok(frame, sizeof(*frame))) + frame = get_sigframe(ksig, regs, frame_size); + if (!access_ok(frame, frame_size)) return -EFAULT; err |= copy_siginfo_to_user(&frame->info, &ksig->info); @@ -320,3 +459,10 @@ void arch_do_signal_or_restart(struct pt_regs *regs) */ restore_saved_sigmask(); } + +void init_rt_signal_env(void); +void __init init_rt_signal_env(void) +{ + riscv_v_sc_size = sizeof(struct __riscv_ctx_hdr) + + sizeof(struct __sc_riscv_v_state) + riscv_v_vsize; +} -- cgit v1.2.3 From e92f469b0771e6db9688a58c0e34a8342da6a6bc Mon Sep 17 00:00:00 2001 From: Vincent Chen Date: Mon, 5 Jun 2023 11:07:12 +0000 Subject: riscv: signal: Report signal frame size to userspace via auxv MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The vector register belongs to the signal context. They need to be stored and restored as entering and leaving the signal handler. According to the V-extension specification, the maximum length of the vector registers can be 2^16. Hence, if userspace refers to the MINSIGSTKSZ to create a sigframe, it may not be enough. To resolve this problem, this patch refers to the commit 94b07c1f8c39c ("arm64: signal: Report signal frame size to userspace via auxv") to enable userspace to know the minimum required sigframe size through the auxiliary vector and use it to allocate enough memory for signal context. Note that auxv always reports size of the sigframe as if V exists for all starting processes, whenever the kernel has CONFIG_RISCV_ISA_V. The reason is that users usually reference this value to allocate an alternative signal stack, and the user may use V anytime. So the user must reserve a space for V-context in sigframe in case that the signal handler invokes after the kernel allocating V. Signed-off-by: Greentime Hu Signed-off-by: Vincent Chen Signed-off-by: Andy Chiu Acked-by: Conor Dooley Reviewed-by: Björn Töpel Reviewed-by: Guo Ren Reviewed-by: Heiko Stuebner Tested-by: Heiko Stuebner Link: https://lore.kernel.org/r/20230605110724.21391-16-andy.chiu@sifive.com Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/elf.h | 9 +++++++++ arch/riscv/include/asm/processor.h | 2 ++ arch/riscv/include/uapi/asm/auxvec.h | 1 + arch/riscv/kernel/signal.c | 20 +++++++++++++++----- 4 files changed, 27 insertions(+), 5 deletions(-) (limited to 'arch/riscv/kernel/signal.c') diff --git a/arch/riscv/include/asm/elf.h b/arch/riscv/include/asm/elf.h index 30e7d2455960..ca23c4f6c440 100644 --- a/arch/riscv/include/asm/elf.h +++ b/arch/riscv/include/asm/elf.h @@ -105,6 +105,15 @@ do { \ get_cache_size(3, CACHE_TYPE_UNIFIED)); \ NEW_AUX_ENT(AT_L3_CACHEGEOMETRY, \ get_cache_geometry(3, CACHE_TYPE_UNIFIED)); \ + /* \ + * 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 struct linux_binprm; diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h index f0ddf691ac5e..38ded8c5f207 100644 --- a/arch/riscv/include/asm/processor.h +++ b/arch/riscv/include/asm/processor.h @@ -7,6 +7,7 @@ #define _ASM_RISCV_PROCESSOR_H #include +#include #include @@ -81,6 +82,7 @@ int riscv_of_parent_hartid(struct device_node *node, unsigned long *hartid); extern void riscv_fill_hwcap(void); extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src); +extern unsigned long signal_minsigstksz __ro_after_init; #endif /* __ASSEMBLY__ */ #endif /* _ASM_RISCV_PROCESSOR_H */ diff --git a/arch/riscv/include/uapi/asm/auxvec.h b/arch/riscv/include/uapi/asm/auxvec.h index fb187a33ce58..10aaa83db89e 100644 --- a/arch/riscv/include/uapi/asm/auxvec.h +++ b/arch/riscv/include/uapi/asm/auxvec.h @@ -35,5 +35,6 @@ /* entries in ARCH_DLINFO */ #define AT_VECTOR_SIZE_ARCH 9 +#define AT_MINSIGSTKSZ 51 #endif /* _UAPI_ASM_RISCV_AUXVEC_H */ diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c index c46f3dc039bb..f117641c1c49 100644 --- a/arch/riscv/kernel/signal.c +++ b/arch/riscv/kernel/signal.c @@ -23,6 +23,8 @@ #include #include +unsigned long signal_minsigstksz __ro_after_init; + extern u32 __user_rt_sigreturn[2]; static size_t riscv_v_sc_size __ro_after_init; @@ -197,7 +199,7 @@ static long restore_sigcontext(struct pt_regs *regs, return err; } -static size_t get_rt_frame_size(void) +static size_t get_rt_frame_size(bool cal_all) { struct rt_sigframe __user *frame; size_t frame_size; @@ -205,8 +207,10 @@ static size_t get_rt_frame_size(void) frame_size = sizeof(*frame); - if (has_vector() && riscv_v_vstate_query(task_pt_regs(current))) - total_context_size += riscv_v_sc_size; + if (has_vector()) { + if (cal_all || riscv_v_vstate_query(task_pt_regs(current))) + total_context_size += riscv_v_sc_size; + } /* * Preserved a __riscv_ctx_hdr for END signal context header if an * extension uses __riscv_extra_ext_header @@ -226,7 +230,7 @@ SYSCALL_DEFINE0(rt_sigreturn) struct rt_sigframe __user *frame; struct task_struct *task; sigset_t set; - size_t frame_size = get_rt_frame_size(); + size_t frame_size = get_rt_frame_size(false); /* Always make any pending restarted system calls return -EINTR */ current->restart_block.fn = do_no_restart_syscall; @@ -323,7 +327,7 @@ static int setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct rt_sigframe __user *frame; long err = 0; unsigned long __maybe_unused addr; - size_t frame_size = get_rt_frame_size(); + size_t frame_size = get_rt_frame_size(false); frame = get_sigframe(ksig, regs, frame_size); if (!access_ok(frame, frame_size)) @@ -465,4 +469,10 @@ void __init init_rt_signal_env(void) { riscv_v_sc_size = sizeof(struct __riscv_ctx_hdr) + sizeof(struct __sc_riscv_v_state) + riscv_v_vsize; + /* + * Determine the stack space required for guaranteed signal delivery. + * The signal_minsigstksz will be populated into the AT_MINSIGSTKSZ entry + * in the auxiliary array at process startup. + */ + signal_minsigstksz = get_rt_frame_size(true); } -- cgit v1.2.3 From 76e22fdc2c2658ab595cdda7368d43d2dc16f3f4 Mon Sep 17 00:00:00 2001 From: Andy Chiu Date: Mon, 5 Jun 2023 11:07:13 +0000 Subject: riscv: signal: validate altstack to reflect Vector Some extensions, such as Vector, dynamically change footprint on a signal frame, so MINSIGSTKSZ is no longer accurate. For example, an RV64V implementation with vlen = 512 may occupy 2K + 40 + 12 Bytes of a signal frame with the upcoming support. And processes that do not execute any vector instructions do not need to reserve the extra sigframe. So we need a way to guard the allocation size of the sigframe at process runtime according to current status of V. Thus, provide the function sigaltstack_size_valid() to validate its size based on current allocation status of supported extensions. Signed-off-by: Andy Chiu Reviewed-by: Conor Dooley Reviewed-by: Heiko Stuebner Tested-by: Heiko Stuebner Link: https://lore.kernel.org/r/20230605110724.21391-17-andy.chiu@sifive.com Signed-off-by: Palmer Dabbelt --- arch/riscv/kernel/signal.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'arch/riscv/kernel/signal.c') diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c index f117641c1c49..180d951d3624 100644 --- a/arch/riscv/kernel/signal.c +++ b/arch/riscv/kernel/signal.c @@ -476,3 +476,10 @@ void __init init_rt_signal_env(void) */ signal_minsigstksz = get_rt_frame_size(true); } + +#ifdef CONFIG_DYNAMIC_SIGFRAME +bool sigaltstack_size_valid(size_t ss_size) +{ + return ss_size > get_rt_frame_size(false); +} +#endif /* CONFIG_DYNAMIC_SIGFRAME */ -- cgit v1.2.3