diff options
Diffstat (limited to 'arch/loongarch/kernel/signal.c')
| -rw-r--r-- | arch/loongarch/kernel/signal.c | 1075 |
1 files changed, 1075 insertions, 0 deletions
diff --git a/arch/loongarch/kernel/signal.c b/arch/loongarch/kernel/signal.c new file mode 100644 index 0000000000..4a3686d133 --- /dev/null +++ b/arch/loongarch/kernel/signal.c @@ -0,0 +1,1075 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Author: Hanlu Li <lihanlu@loongson.cn> + * Huacai Chen <chenhuacai@loongson.cn> + * Copyright (C) 2020-2022 Loongson Technology Corporation Limited + * + * Derived from MIPS: + * Copyright (C) 1991, 1992 Linus Torvalds + * Copyright (C) 1994 - 2000 Ralf Baechle + * Copyright (C) 1999, 2000 Silicon Graphics, Inc. + * Copyright (C) 2014, Imagination Technologies Ltd. + */ +#include <linux/audit.h> +#include <linux/cache.h> +#include <linux/context_tracking.h> +#include <linux/entry-common.h> +#include <linux/irqflags.h> +#include <linux/sched.h> +#include <linux/mm.h> +#include <linux/personality.h> +#include <linux/smp.h> +#include <linux/kernel.h> +#include <linux/signal.h> +#include <linux/errno.h> +#include <linux/wait.h> +#include <linux/ptrace.h> +#include <linux/unistd.h> +#include <linux/compiler.h> +#include <linux/syscalls.h> +#include <linux/uaccess.h> + +#include <asm/asm.h> +#include <asm/cacheflush.h> +#include <asm/cpu-features.h> +#include <asm/fpu.h> +#include <asm/lbt.h> +#include <asm/ucontext.h> +#include <asm/vdso.h> + +#ifdef DEBUG_SIG +# define DEBUGP(fmt, args...) printk("%s: " fmt, __func__, ##args) +#else +# define DEBUGP(fmt, args...) +#endif + +/* Make sure we will not lose FPU ownership */ +#define lock_fpu_owner() ({ preempt_disable(); pagefault_disable(); }) +#define unlock_fpu_owner() ({ pagefault_enable(); preempt_enable(); }) +/* Make sure we will not lose LBT ownership */ +#define lock_lbt_owner() ({ preempt_disable(); pagefault_disable(); }) +#define unlock_lbt_owner() ({ pagefault_enable(); preempt_enable(); }) + +/* Assembly functions to move context to/from the FPU */ +extern asmlinkage int +_save_fp_context(void __user *fpregs, void __user *fcc, void __user *csr); +extern asmlinkage int +_restore_fp_context(void __user *fpregs, void __user *fcc, void __user *csr); +extern asmlinkage int +_save_lsx_context(void __user *fpregs, void __user *fcc, void __user *fcsr); +extern asmlinkage int +_restore_lsx_context(void __user *fpregs, void __user *fcc, void __user *fcsr); +extern asmlinkage int +_save_lasx_context(void __user *fpregs, void __user *fcc, void __user *fcsr); +extern asmlinkage int +_restore_lasx_context(void __user *fpregs, void __user *fcc, void __user *fcsr); + +#ifdef CONFIG_CPU_HAS_LBT +extern asmlinkage int _save_lbt_context(void __user *regs, void __user *eflags); +extern asmlinkage int _restore_lbt_context(void __user *regs, void __user *eflags); +extern asmlinkage int _save_ftop_context(void __user *ftop); +extern asmlinkage int _restore_ftop_context(void __user *ftop); +#endif + +struct rt_sigframe { + struct siginfo rs_info; + struct ucontext rs_uctx; +}; + +struct _ctx_layout { + struct sctx_info *addr; + unsigned int size; +}; + +struct extctx_layout { + unsigned long size; + unsigned int flags; + struct _ctx_layout fpu; + struct _ctx_layout lsx; + struct _ctx_layout lasx; + struct _ctx_layout lbt; + struct _ctx_layout end; +}; + +static void __user *get_ctx_through_ctxinfo(struct sctx_info *info) +{ + return (void __user *)((char *)info + sizeof(struct sctx_info)); +} + +/* + * Thread saved context copy to/from a signal context presumed to be on the + * user stack, and therefore accessed with appropriate macros from uaccess.h. + */ +static int copy_fpu_to_sigcontext(struct fpu_context __user *ctx) +{ + int i; + int err = 0; + uint64_t __user *regs = (uint64_t *)&ctx->regs; + uint64_t __user *fcc = &ctx->fcc; + uint32_t __user *fcsr = &ctx->fcsr; + + for (i = 0; i < NUM_FPU_REGS; i++) { + err |= + __put_user(get_fpr64(¤t->thread.fpu.fpr[i], 0), + ®s[i]); + } + err |= __put_user(current->thread.fpu.fcc, fcc); + err |= __put_user(current->thread.fpu.fcsr, fcsr); + + return err; +} + +static int copy_fpu_from_sigcontext(struct fpu_context __user *ctx) +{ + int i; + int err = 0; + u64 fpr_val; + uint64_t __user *regs = (uint64_t *)&ctx->regs; + uint64_t __user *fcc = &ctx->fcc; + uint32_t __user *fcsr = &ctx->fcsr; + + for (i = 0; i < NUM_FPU_REGS; i++) { + err |= __get_user(fpr_val, ®s[i]); + set_fpr64(¤t->thread.fpu.fpr[i], 0, fpr_val); + } + err |= __get_user(current->thread.fpu.fcc, fcc); + err |= __get_user(current->thread.fpu.fcsr, fcsr); + + return err; +} + +static int copy_lsx_to_sigcontext(struct lsx_context __user *ctx) +{ + int i; + int err = 0; + uint64_t __user *regs = (uint64_t *)&ctx->regs; + uint64_t __user *fcc = &ctx->fcc; + uint32_t __user *fcsr = &ctx->fcsr; + + for (i = 0; i < NUM_FPU_REGS; i++) { + err |= __put_user(get_fpr64(¤t->thread.fpu.fpr[i], 0), + ®s[2*i]); + err |= __put_user(get_fpr64(¤t->thread.fpu.fpr[i], 1), + ®s[2*i+1]); + } + err |= __put_user(current->thread.fpu.fcc, fcc); + err |= __put_user(current->thread.fpu.fcsr, fcsr); + + return err; +} + +static int copy_lsx_from_sigcontext(struct lsx_context __user *ctx) +{ + int i; + int err = 0; + u64 fpr_val; + uint64_t __user *regs = (uint64_t *)&ctx->regs; + uint64_t __user *fcc = &ctx->fcc; + uint32_t __user *fcsr = &ctx->fcsr; + + for (i = 0; i < NUM_FPU_REGS; i++) { + err |= __get_user(fpr_val, ®s[2*i]); + set_fpr64(¤t->thread.fpu.fpr[i], 0, fpr_val); + err |= __get_user(fpr_val, ®s[2*i+1]); + set_fpr64(¤t->thread.fpu.fpr[i], 1, fpr_val); + } + err |= __get_user(current->thread.fpu.fcc, fcc); + err |= __get_user(current->thread.fpu.fcsr, fcsr); + + return err; +} + +static int copy_lasx_to_sigcontext(struct lasx_context __user *ctx) +{ + int i; + int err = 0; + uint64_t __user *regs = (uint64_t *)&ctx->regs; + uint64_t __user *fcc = &ctx->fcc; + uint32_t __user *fcsr = &ctx->fcsr; + + for (i = 0; i < NUM_FPU_REGS; i++) { + err |= __put_user(get_fpr64(¤t->thread.fpu.fpr[i], 0), + ®s[4*i]); + err |= __put_user(get_fpr64(¤t->thread.fpu.fpr[i], 1), + ®s[4*i+1]); + err |= __put_user(get_fpr64(¤t->thread.fpu.fpr[i], 2), + ®s[4*i+2]); + err |= __put_user(get_fpr64(¤t->thread.fpu.fpr[i], 3), + ®s[4*i+3]); + } + err |= __put_user(current->thread.fpu.fcc, fcc); + err |= __put_user(current->thread.fpu.fcsr, fcsr); + + return err; +} + +static int copy_lasx_from_sigcontext(struct lasx_context __user *ctx) +{ + int i; + int err = 0; + u64 fpr_val; + uint64_t __user *regs = (uint64_t *)&ctx->regs; + uint64_t __user *fcc = &ctx->fcc; + uint32_t __user *fcsr = &ctx->fcsr; + + for (i = 0; i < NUM_FPU_REGS; i++) { + err |= __get_user(fpr_val, ®s[4*i]); + set_fpr64(¤t->thread.fpu.fpr[i], 0, fpr_val); + err |= __get_user(fpr_val, ®s[4*i+1]); + set_fpr64(¤t->thread.fpu.fpr[i], 1, fpr_val); + err |= __get_user(fpr_val, ®s[4*i+2]); + set_fpr64(¤t->thread.fpu.fpr[i], 2, fpr_val); + err |= __get_user(fpr_val, ®s[4*i+3]); + set_fpr64(¤t->thread.fpu.fpr[i], 3, fpr_val); + } + err |= __get_user(current->thread.fpu.fcc, fcc); + err |= __get_user(current->thread.fpu.fcsr, fcsr); + + return err; +} + +#ifdef CONFIG_CPU_HAS_LBT +static int copy_lbt_to_sigcontext(struct lbt_context __user *ctx) +{ + int err = 0; + uint64_t __user *regs = (uint64_t *)&ctx->regs; + uint32_t __user *eflags = (uint32_t *)&ctx->eflags; + + err |= __put_user(current->thread.lbt.scr0, ®s[0]); + err |= __put_user(current->thread.lbt.scr1, ®s[1]); + err |= __put_user(current->thread.lbt.scr2, ®s[2]); + err |= __put_user(current->thread.lbt.scr3, ®s[3]); + err |= __put_user(current->thread.lbt.eflags, eflags); + + return err; +} + +static int copy_lbt_from_sigcontext(struct lbt_context __user *ctx) +{ + int err = 0; + uint64_t __user *regs = (uint64_t *)&ctx->regs; + uint32_t __user *eflags = (uint32_t *)&ctx->eflags; + + err |= __get_user(current->thread.lbt.scr0, ®s[0]); + err |= __get_user(current->thread.lbt.scr1, ®s[1]); + err |= __get_user(current->thread.lbt.scr2, ®s[2]); + err |= __get_user(current->thread.lbt.scr3, ®s[3]); + err |= __get_user(current->thread.lbt.eflags, eflags); + + return err; +} + +static int copy_ftop_to_sigcontext(struct lbt_context __user *ctx) +{ + uint32_t __user *ftop = &ctx->ftop; + + return __put_user(current->thread.fpu.ftop, ftop); +} + +static int copy_ftop_from_sigcontext(struct lbt_context __user *ctx) +{ + uint32_t __user *ftop = &ctx->ftop; + + return __get_user(current->thread.fpu.ftop, ftop); +} +#endif + +/* + * Wrappers for the assembly _{save,restore}_fp_context functions. + */ +static int save_hw_fpu_context(struct fpu_context __user *ctx) +{ + uint64_t __user *regs = (uint64_t *)&ctx->regs; + uint64_t __user *fcc = &ctx->fcc; + uint32_t __user *fcsr = &ctx->fcsr; + + return _save_fp_context(regs, fcc, fcsr); +} + +static int restore_hw_fpu_context(struct fpu_context __user *ctx) +{ + uint64_t __user *regs = (uint64_t *)&ctx->regs; + uint64_t __user *fcc = &ctx->fcc; + uint32_t __user *fcsr = &ctx->fcsr; + + return _restore_fp_context(regs, fcc, fcsr); +} + +static int save_hw_lsx_context(struct lsx_context __user *ctx) +{ + uint64_t __user *regs = (uint64_t *)&ctx->regs; + uint64_t __user *fcc = &ctx->fcc; + uint32_t __user *fcsr = &ctx->fcsr; + + return _save_lsx_context(regs, fcc, fcsr); +} + +static int restore_hw_lsx_context(struct lsx_context __user *ctx) +{ + uint64_t __user *regs = (uint64_t *)&ctx->regs; + uint64_t __user *fcc = &ctx->fcc; + uint32_t __user *fcsr = &ctx->fcsr; + + return _restore_lsx_context(regs, fcc, fcsr); +} + +static int save_hw_lasx_context(struct lasx_context __user *ctx) +{ + uint64_t __user *regs = (uint64_t *)&ctx->regs; + uint64_t __user *fcc = &ctx->fcc; + uint32_t __user *fcsr = &ctx->fcsr; + + return _save_lasx_context(regs, fcc, fcsr); +} + +static int restore_hw_lasx_context(struct lasx_context __user *ctx) +{ + uint64_t __user *regs = (uint64_t *)&ctx->regs; + uint64_t __user *fcc = &ctx->fcc; + uint32_t __user *fcsr = &ctx->fcsr; + + return _restore_lasx_context(regs, fcc, fcsr); +} + +/* + * Wrappers for the assembly _{save,restore}_lbt_context functions. + */ +#ifdef CONFIG_CPU_HAS_LBT +static int save_hw_lbt_context(struct lbt_context __user *ctx) +{ + uint64_t __user *regs = (uint64_t *)&ctx->regs; + uint32_t __user *eflags = (uint32_t *)&ctx->eflags; + + return _save_lbt_context(regs, eflags); +} + +static int restore_hw_lbt_context(struct lbt_context __user *ctx) +{ + uint64_t __user *regs = (uint64_t *)&ctx->regs; + uint32_t __user *eflags = (uint32_t *)&ctx->eflags; + + return _restore_lbt_context(regs, eflags); +} + +static int save_hw_ftop_context(struct lbt_context __user *ctx) +{ + uint32_t __user *ftop = &ctx->ftop; + + return _save_ftop_context(ftop); +} + +static int restore_hw_ftop_context(struct lbt_context __user *ctx) +{ + uint32_t __user *ftop = &ctx->ftop; + + return _restore_ftop_context(ftop); +} +#endif + +static int fcsr_pending(unsigned int __user *fcsr) +{ + int err, sig = 0; + unsigned int csr, enabled; + + err = __get_user(csr, fcsr); + enabled = ((csr & FPU_CSR_ALL_E) << 24); + /* + * If the signal handler set some FPU exceptions, clear it and + * send SIGFPE. + */ + if (csr & enabled) { + csr &= ~enabled; + err |= __put_user(csr, fcsr); + sig = SIGFPE; + } + return err ?: sig; +} + +/* + * Helper routines + */ +static int protected_save_fpu_context(struct extctx_layout *extctx) +{ + int err = 0; + struct sctx_info __user *info = extctx->fpu.addr; + struct fpu_context __user *fpu_ctx = (struct fpu_context *)get_ctx_through_ctxinfo(info); + uint64_t __user *regs = (uint64_t *)&fpu_ctx->regs; + uint64_t __user *fcc = &fpu_ctx->fcc; + uint32_t __user *fcsr = &fpu_ctx->fcsr; + + while (1) { + lock_fpu_owner(); + if (is_fpu_owner()) + err = save_hw_fpu_context(fpu_ctx); + else + err = copy_fpu_to_sigcontext(fpu_ctx); + unlock_fpu_owner(); + + err |= __put_user(FPU_CTX_MAGIC, &info->magic); + err |= __put_user(extctx->fpu.size, &info->size); + + if (likely(!err)) + break; + /* Touch the FPU context and try again */ + err = __put_user(0, ®s[0]) | + __put_user(0, ®s[31]) | + __put_user(0, fcc) | + __put_user(0, fcsr); + if (err) + return err; /* really bad sigcontext */ + } + + return err; +} + +static int protected_restore_fpu_context(struct extctx_layout *extctx) +{ + int err = 0, sig = 0, tmp __maybe_unused; + struct sctx_info __user *info = extctx->fpu.addr; + struct fpu_context __user *fpu_ctx = (struct fpu_context *)get_ctx_through_ctxinfo(info); + uint64_t __user *regs = (uint64_t *)&fpu_ctx->regs; + uint64_t __user *fcc = &fpu_ctx->fcc; + uint32_t __user *fcsr = &fpu_ctx->fcsr; + + err = sig = fcsr_pending(fcsr); + if (err < 0) + return err; + + while (1) { + lock_fpu_owner(); + if (is_fpu_owner()) + err = restore_hw_fpu_context(fpu_ctx); + else + err = copy_fpu_from_sigcontext(fpu_ctx); + unlock_fpu_owner(); + + if (likely(!err)) + break; + /* Touch the FPU context and try again */ + err = __get_user(tmp, ®s[0]) | + __get_user(tmp, ®s[31]) | + __get_user(tmp, fcc) | + __get_user(tmp, fcsr); + if (err) + break; /* really bad sigcontext */ + } + + return err ?: sig; +} + +static int protected_save_lsx_context(struct extctx_layout *extctx) +{ + int err = 0; + struct sctx_info __user *info = extctx->lsx.addr; + struct lsx_context __user *lsx_ctx = (struct lsx_context *)get_ctx_through_ctxinfo(info); + uint64_t __user *regs = (uint64_t *)&lsx_ctx->regs; + uint64_t __user *fcc = &lsx_ctx->fcc; + uint32_t __user *fcsr = &lsx_ctx->fcsr; + + while (1) { + lock_fpu_owner(); + if (is_lsx_enabled()) + err = save_hw_lsx_context(lsx_ctx); + else { + if (is_fpu_owner()) + save_fp(current); + err = copy_lsx_to_sigcontext(lsx_ctx); + } + unlock_fpu_owner(); + + err |= __put_user(LSX_CTX_MAGIC, &info->magic); + err |= __put_user(extctx->lsx.size, &info->size); + + if (likely(!err)) + break; + /* Touch the LSX context and try again */ + err = __put_user(0, ®s[0]) | + __put_user(0, ®s[32*2-1]) | + __put_user(0, fcc) | + __put_user(0, fcsr); + if (err) + return err; /* really bad sigcontext */ + } + + return err; +} + +static int protected_restore_lsx_context(struct extctx_layout *extctx) +{ + int err = 0, sig = 0, tmp __maybe_unused; + struct sctx_info __user *info = extctx->lsx.addr; + struct lsx_context __user *lsx_ctx = (struct lsx_context *)get_ctx_through_ctxinfo(info); + uint64_t __user *regs = (uint64_t *)&lsx_ctx->regs; + uint64_t __user *fcc = &lsx_ctx->fcc; + uint32_t __user *fcsr = &lsx_ctx->fcsr; + + err = sig = fcsr_pending(fcsr); + if (err < 0) + return err; + + while (1) { + lock_fpu_owner(); + if (is_lsx_enabled()) + err = restore_hw_lsx_context(lsx_ctx); + else { + err = copy_lsx_from_sigcontext(lsx_ctx); + if (is_fpu_owner()) + restore_fp(current); + } + unlock_fpu_owner(); + + if (likely(!err)) + break; + /* Touch the LSX context and try again */ + err = __get_user(tmp, ®s[0]) | + __get_user(tmp, ®s[32*2-1]) | + __get_user(tmp, fcc) | + __get_user(tmp, fcsr); + if (err) + break; /* really bad sigcontext */ + } + + return err ?: sig; +} + +static int protected_save_lasx_context(struct extctx_layout *extctx) +{ + int err = 0; + struct sctx_info __user *info = extctx->lasx.addr; + struct lasx_context __user *lasx_ctx = + (struct lasx_context *)get_ctx_through_ctxinfo(info); + uint64_t __user *regs = (uint64_t *)&lasx_ctx->regs; + uint64_t __user *fcc = &lasx_ctx->fcc; + uint32_t __user *fcsr = &lasx_ctx->fcsr; + + while (1) { + lock_fpu_owner(); + if (is_lasx_enabled()) + err = save_hw_lasx_context(lasx_ctx); + else { + if (is_lsx_enabled()) + save_lsx(current); + else if (is_fpu_owner()) + save_fp(current); + err = copy_lasx_to_sigcontext(lasx_ctx); + } + unlock_fpu_owner(); + + err |= __put_user(LASX_CTX_MAGIC, &info->magic); + err |= __put_user(extctx->lasx.size, &info->size); + + if (likely(!err)) + break; + /* Touch the LASX context and try again */ + err = __put_user(0, ®s[0]) | + __put_user(0, ®s[32*4-1]) | + __put_user(0, fcc) | + __put_user(0, fcsr); + if (err) + return err; /* really bad sigcontext */ + } + + return err; +} + +static int protected_restore_lasx_context(struct extctx_layout *extctx) +{ + int err = 0, sig = 0, tmp __maybe_unused; + struct sctx_info __user *info = extctx->lasx.addr; + struct lasx_context __user *lasx_ctx = + (struct lasx_context *)get_ctx_through_ctxinfo(info); + uint64_t __user *regs = (uint64_t *)&lasx_ctx->regs; + uint64_t __user *fcc = &lasx_ctx->fcc; + uint32_t __user *fcsr = &lasx_ctx->fcsr; + + err = sig = fcsr_pending(fcsr); + if (err < 0) + return err; + + while (1) { + lock_fpu_owner(); + if (is_lasx_enabled()) + err = restore_hw_lasx_context(lasx_ctx); + else { + err = copy_lasx_from_sigcontext(lasx_ctx); + if (is_lsx_enabled()) + restore_lsx(current); + else if (is_fpu_owner()) + restore_fp(current); + } + unlock_fpu_owner(); + + if (likely(!err)) + break; + /* Touch the LASX context and try again */ + err = __get_user(tmp, ®s[0]) | + __get_user(tmp, ®s[32*4-1]) | + __get_user(tmp, fcc) | + __get_user(tmp, fcsr); + if (err) + break; /* really bad sigcontext */ + } + + return err ?: sig; +} + +#ifdef CONFIG_CPU_HAS_LBT +static int protected_save_lbt_context(struct extctx_layout *extctx) +{ + int err = 0; + struct sctx_info __user *info = extctx->lbt.addr; + struct lbt_context __user *lbt_ctx = + (struct lbt_context *)get_ctx_through_ctxinfo(info); + uint64_t __user *regs = (uint64_t *)&lbt_ctx->regs; + uint32_t __user *eflags = (uint32_t *)&lbt_ctx->eflags; + + while (1) { + lock_lbt_owner(); + if (is_lbt_owner()) + err |= save_hw_lbt_context(lbt_ctx); + else + err |= copy_lbt_to_sigcontext(lbt_ctx); + if (is_fpu_owner()) + err |= save_hw_ftop_context(lbt_ctx); + else + err |= copy_ftop_to_sigcontext(lbt_ctx); + unlock_lbt_owner(); + + err |= __put_user(LBT_CTX_MAGIC, &info->magic); + err |= __put_user(extctx->lbt.size, &info->size); + + if (likely(!err)) + break; + /* Touch the LBT context and try again */ + err = __put_user(0, ®s[0]) | __put_user(0, eflags); + + if (err) + return err; + } + + return err; +} + +static int protected_restore_lbt_context(struct extctx_layout *extctx) +{ + int err = 0, tmp __maybe_unused; + struct sctx_info __user *info = extctx->lbt.addr; + struct lbt_context __user *lbt_ctx = + (struct lbt_context *)get_ctx_through_ctxinfo(info); + uint64_t __user *regs = (uint64_t *)&lbt_ctx->regs; + uint32_t __user *eflags = (uint32_t *)&lbt_ctx->eflags; + + while (1) { + lock_lbt_owner(); + if (is_lbt_owner()) + err |= restore_hw_lbt_context(lbt_ctx); + else + err |= copy_lbt_from_sigcontext(lbt_ctx); + if (is_fpu_owner()) + err |= restore_hw_ftop_context(lbt_ctx); + else + err |= copy_ftop_from_sigcontext(lbt_ctx); + unlock_lbt_owner(); + + if (likely(!err)) + break; + /* Touch the LBT context and try again */ + err = __get_user(tmp, ®s[0]) | __get_user(tmp, eflags); + + if (err) + return err; + } + + return err; +} +#endif + +static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, + struct extctx_layout *extctx) +{ + int i, err = 0; + struct sctx_info __user *info; + + err |= __put_user(regs->csr_era, &sc->sc_pc); + err |= __put_user(extctx->flags, &sc->sc_flags); + + err |= __put_user(0, &sc->sc_regs[0]); + for (i = 1; i < 32; i++) + err |= __put_user(regs->regs[i], &sc->sc_regs[i]); + + if (extctx->lasx.addr) + err |= protected_save_lasx_context(extctx); + else if (extctx->lsx.addr) + err |= protected_save_lsx_context(extctx); + else if (extctx->fpu.addr) + err |= protected_save_fpu_context(extctx); + +#ifdef CONFIG_CPU_HAS_LBT + if (extctx->lbt.addr) + err |= protected_save_lbt_context(extctx); +#endif + + /* Set the "end" magic */ + info = (struct sctx_info *)extctx->end.addr; + err |= __put_user(0, &info->magic); + err |= __put_user(0, &info->size); + + return err; +} + +static int parse_extcontext(struct sigcontext __user *sc, struct extctx_layout *extctx) +{ + int err = 0; + unsigned int magic, size; + struct sctx_info __user *info = (struct sctx_info __user *)&sc->sc_extcontext; + + while(1) { + err |= __get_user(magic, &info->magic); + err |= __get_user(size, &info->size); + if (err) + return err; + + switch (magic) { + case 0: /* END */ + goto done; + + case FPU_CTX_MAGIC: + if (size < (sizeof(struct sctx_info) + + sizeof(struct fpu_context))) + goto invalid; + extctx->fpu.addr = info; + break; + + case LSX_CTX_MAGIC: + if (size < (sizeof(struct sctx_info) + + sizeof(struct lsx_context))) + goto invalid; + extctx->lsx.addr = info; + break; + + case LASX_CTX_MAGIC: + if (size < (sizeof(struct sctx_info) + + sizeof(struct lasx_context))) + goto invalid; + extctx->lasx.addr = info; + break; + + case LBT_CTX_MAGIC: + if (size < (sizeof(struct sctx_info) + + sizeof(struct lbt_context))) + goto invalid; + extctx->lbt.addr = info; + break; + + default: + goto invalid; + } + + info = (struct sctx_info *)((char *)info + size); + } + +done: + return 0; + +invalid: + return -EINVAL; +} + +static int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) +{ + int i, err = 0; + struct extctx_layout extctx; + + memset(&extctx, 0, sizeof(struct extctx_layout)); + + err = __get_user(extctx.flags, &sc->sc_flags); + if (err) + goto bad; + + err = parse_extcontext(sc, &extctx); + if (err) + goto bad; + + conditional_used_math(extctx.flags & SC_USED_FP); + + /* + * The signal handler may have used FPU; give it up if the program + * doesn't want it following sigreturn. + */ + if (!(extctx.flags & SC_USED_FP)) + lose_fpu(0); + + /* Always make any pending restarted system calls return -EINTR */ + current->restart_block.fn = do_no_restart_syscall; + + err |= __get_user(regs->csr_era, &sc->sc_pc); + for (i = 1; i < 32; i++) + err |= __get_user(regs->regs[i], &sc->sc_regs[i]); + + if (extctx.lasx.addr) + err |= protected_restore_lasx_context(&extctx); + else if (extctx.lsx.addr) + err |= protected_restore_lsx_context(&extctx); + else if (extctx.fpu.addr) + err |= protected_restore_fpu_context(&extctx); + +#ifdef CONFIG_CPU_HAS_LBT + if (extctx.lbt.addr) + err |= protected_restore_lbt_context(&extctx); +#endif + +bad: + return err; +} + +static unsigned int handle_flags(void) +{ + unsigned int flags = 0; + + flags = used_math() ? SC_USED_FP : 0; + + switch (current->thread.error_code) { + case 1: + flags |= SC_ADDRERR_RD; + break; + case 2: + flags |= SC_ADDRERR_WR; + break; + } + + return flags; +} + +static unsigned long extframe_alloc(struct extctx_layout *extctx, + struct _ctx_layout *layout, + size_t size, unsigned int align, unsigned long base) +{ + unsigned long new_base = base - size; + + new_base = round_down(new_base, (align < 16 ? 16 : align)); + new_base -= sizeof(struct sctx_info); + + layout->addr = (void *)new_base; + layout->size = (unsigned int)(base - new_base); + extctx->size += layout->size; + + return new_base; +} + +static unsigned long setup_extcontext(struct extctx_layout *extctx, unsigned long sp) +{ + unsigned long new_sp = sp; + + memset(extctx, 0, sizeof(struct extctx_layout)); + + extctx->flags = handle_flags(); + + /* Grow down, alloc "end" context info first. */ + new_sp -= sizeof(struct sctx_info); + extctx->end.addr = (void *)new_sp; + extctx->end.size = (unsigned int)sizeof(struct sctx_info); + extctx->size += extctx->end.size; + + if (extctx->flags & SC_USED_FP) { + if (cpu_has_lasx && thread_lasx_context_live()) + new_sp = extframe_alloc(extctx, &extctx->lasx, + sizeof(struct lasx_context), LASX_CTX_ALIGN, new_sp); + else if (cpu_has_lsx && thread_lsx_context_live()) + new_sp = extframe_alloc(extctx, &extctx->lsx, + sizeof(struct lsx_context), LSX_CTX_ALIGN, new_sp); + else if (cpu_has_fpu) + new_sp = extframe_alloc(extctx, &extctx->fpu, + sizeof(struct fpu_context), FPU_CTX_ALIGN, new_sp); + } + +#ifdef CONFIG_CPU_HAS_LBT + if (cpu_has_lbt && thread_lbt_context_live()) { + new_sp = extframe_alloc(extctx, &extctx->lbt, + sizeof(struct lbt_context), LBT_CTX_ALIGN, new_sp); + } +#endif + + return new_sp; +} + +static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, + struct extctx_layout *extctx) +{ + unsigned long sp; + + /* Default to using normal stack */ + sp = regs->regs[3]; + + /* + * If we are on the alternate signal stack and would overflow it, don't. + * Return an always-bogus address instead so we will die with SIGSEGV. + */ + if (on_sig_stack(sp) && + !likely(on_sig_stack(sp - sizeof(struct rt_sigframe)))) + return (void __user __force *)(-1UL); + + sp = sigsp(sp, ksig); + sp = round_down(sp, 16); + sp = setup_extcontext(extctx, sp); + sp -= sizeof(struct rt_sigframe); + + if (!IS_ALIGNED(sp, 16)) + BUG(); + + return (void __user *)sp; +} + +/* + * Atomically swap in the new signal mask, and wait for a signal. + */ + +SYSCALL_DEFINE0(rt_sigreturn) +{ + int sig; + sigset_t set; + struct pt_regs *regs; + struct rt_sigframe __user *frame; + + regs = current_pt_regs(); + frame = (struct rt_sigframe __user *)regs->regs[3]; + if (!access_ok(frame, sizeof(*frame))) + goto badframe; + if (__copy_from_user(&set, &frame->rs_uctx.uc_sigmask, sizeof(set))) + goto badframe; + + set_current_blocked(&set); + + sig = restore_sigcontext(regs, &frame->rs_uctx.uc_mcontext); + if (sig < 0) + goto badframe; + else if (sig) + force_sig(sig); + + regs->regs[0] = 0; /* No syscall restarting */ + if (restore_altstack(&frame->rs_uctx.uc_stack)) + goto badframe; + + return regs->regs[4]; + +badframe: + force_sig(SIGSEGV); + return 0; +} + +static int setup_rt_frame(void *sig_return, struct ksignal *ksig, + struct pt_regs *regs, sigset_t *set) +{ + int err = 0; + struct extctx_layout extctx; + struct rt_sigframe __user *frame; + + frame = get_sigframe(ksig, regs, &extctx); + if (!access_ok(frame, sizeof(*frame) + extctx.size)) + return -EFAULT; + + /* Create siginfo. */ + err |= copy_siginfo_to_user(&frame->rs_info, &ksig->info); + + /* Create the ucontext. */ + err |= __put_user(0, &frame->rs_uctx.uc_flags); + err |= __put_user(NULL, &frame->rs_uctx.uc_link); + err |= __save_altstack(&frame->rs_uctx.uc_stack, regs->regs[3]); + err |= setup_sigcontext(regs, &frame->rs_uctx.uc_mcontext, &extctx); + err |= __copy_to_user(&frame->rs_uctx.uc_sigmask, set, sizeof(*set)); + + if (err) + return -EFAULT; + + /* + * Arguments to signal handler: + * + * a0 = signal number + * a1 = pointer to siginfo + * a2 = pointer to ucontext + * + * c0_era point to the signal handler, $r3 (sp) points to + * the struct rt_sigframe. + */ + regs->regs[4] = ksig->sig; + regs->regs[5] = (unsigned long) &frame->rs_info; + regs->regs[6] = (unsigned long) &frame->rs_uctx; + regs->regs[3] = (unsigned long) frame; + regs->regs[1] = (unsigned long) sig_return; + regs->csr_era = (unsigned long) ksig->ka.sa.sa_handler; + + DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n", + current->comm, current->pid, + frame, regs->csr_era, regs->regs[1]); + + return 0; +} + +static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) +{ + int ret; + sigset_t *oldset = sigmask_to_save(); + void *vdso = current->mm->context.vdso; + + /* Are we from a system call? */ + if (regs->regs[0]) { + switch (regs->regs[4]) { + case -ERESTART_RESTARTBLOCK: + case -ERESTARTNOHAND: + regs->regs[4] = -EINTR; + break; + case -ERESTARTSYS: + if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { + regs->regs[4] = -EINTR; + break; + } + fallthrough; + case -ERESTARTNOINTR: + regs->regs[4] = regs->orig_a0; + regs->csr_era -= 4; + } + + regs->regs[0] = 0; /* Don't deal with this again. */ + } + + rseq_signal_deliver(ksig, regs); + + ret = setup_rt_frame(vdso + current->thread.vdso->offset_sigreturn, ksig, regs, oldset); + + signal_setup_done(ret, ksig, 0); +} + +void arch_do_signal_or_restart(struct pt_regs *regs) +{ + struct ksignal ksig; + + if (get_signal(&ksig)) { + /* Whee! Actually deliver the signal. */ + handle_signal(&ksig, regs); + return; + } + + /* Are we from a system call? */ + if (regs->regs[0]) { + switch (regs->regs[4]) { + case -ERESTARTNOHAND: + case -ERESTARTSYS: + case -ERESTARTNOINTR: + regs->regs[4] = regs->orig_a0; + regs->csr_era -= 4; + break; + + case -ERESTART_RESTARTBLOCK: + regs->regs[4] = regs->orig_a0; + regs->regs[11] = __NR_restart_syscall; + regs->csr_era -= 4; + break; + } + regs->regs[0] = 0; /* Don't deal with this again. */ + } + + /* + * If there's no signal to deliver, we just put the saved sigmask + * back + */ + restore_saved_sigmask(); +} |