diff options
| -rw-r--r-- | arch/arm64/include/asm/fpsimd.h | 3 | ||||
| -rw-r--r-- | arch/arm64/include/uapi/asm/sigcontext.h | 19 | ||||
| -rw-r--r-- | arch/arm64/kernel/signal.c | 105 |
3 files changed, 124 insertions, 3 deletions
diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h index 0ce4465644fc..67f2fb781f59 100644 --- a/arch/arm64/include/asm/fpsimd.h +++ b/arch/arm64/include/asm/fpsimd.h @@ -361,9 +361,6 @@ extern unsigned int sme_get_vl(void); extern int sme_set_current_vl(unsigned long arg); extern int sme_get_current_vl(void); -/* Will move with signal support */ -#define ZT_SIG_REG_SIZE 512 - /* * Return how many bytes of memory are required to store the full SME * specific state for task, given task's currently configured vector diff --git a/arch/arm64/include/uapi/asm/sigcontext.h b/arch/arm64/include/uapi/asm/sigcontext.h index 9525041e4a14..46e9072985a5 100644 --- a/arch/arm64/include/uapi/asm/sigcontext.h +++ b/arch/arm64/include/uapi/asm/sigcontext.h @@ -152,6 +152,14 @@ struct za_context { __u16 __reserved[3]; }; +#define ZT_MAGIC 0x5a544e01 + +struct zt_context { + struct _aarch64_ctx head; + __u16 nregs; + __u16 __reserved[3]; +}; + #endif /* !__ASSEMBLY__ */ #include <asm/sve_context.h> @@ -304,4 +312,15 @@ struct za_context { #define ZA_SIG_CONTEXT_SIZE(vq) \ (ZA_SIG_REGS_OFFSET + ZA_SIG_REGS_SIZE(vq)) +#define ZT_SIG_REG_SIZE 512 + +#define ZT_SIG_REG_BYTES (ZT_SIG_REG_SIZE / 8) + +#define ZT_SIG_REGS_OFFSET sizeof(struct zt_context) + +#define ZT_SIG_REGS_SIZE(n) (ZT_SIG_REG_BYTES * n) + +#define ZT_SIG_CONTEXT_SIZE(n) \ + (sizeof(struct zt_context) + ZT_SIG_REGS_SIZE(n)) + #endif /* _UAPI__ASM_SIGCONTEXT_H */ diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 27768809dd3e..1c5e557a3617 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -57,6 +57,7 @@ struct rt_sigframe_user_layout { unsigned long esr_offset; unsigned long sve_offset; unsigned long za_offset; + unsigned long zt_offset; unsigned long extra_offset; unsigned long end_offset; }; @@ -221,6 +222,7 @@ struct user_ctxs { struct fpsimd_context __user *fpsimd; struct sve_context __user *sve; struct za_context __user *za; + struct zt_context __user *zt; }; #ifdef CONFIG_ARM64_SVE @@ -447,11 +449,81 @@ static int restore_za_context(struct user_ctxs *user) return 0; } + +static int preserve_zt_context(struct zt_context __user *ctx) +{ + int err = 0; + u16 reserved[ARRAY_SIZE(ctx->__reserved)]; + + if (WARN_ON(!thread_za_enabled(¤t->thread))) + return -EINVAL; + + memset(reserved, 0, sizeof(reserved)); + + __put_user_error(ZT_MAGIC, &ctx->head.magic, err); + __put_user_error(round_up(ZT_SIG_CONTEXT_SIZE(1), 16), + &ctx->head.size, err); + __put_user_error(1, &ctx->nregs, err); + BUILD_BUG_ON(sizeof(ctx->__reserved) != sizeof(reserved)); + err |= __copy_to_user(&ctx->__reserved, reserved, sizeof(reserved)); + + /* + * This assumes that the ZT state has already been saved to + * the task struct by calling the function + * fpsimd_signal_preserve_current_state(). + */ + err |= __copy_to_user((char __user *)ctx + ZT_SIG_REGS_OFFSET, + thread_zt_state(¤t->thread), + ZT_SIG_REGS_SIZE(1)); + + return err ? -EFAULT : 0; +} + +static int restore_zt_context(struct user_ctxs *user) +{ + int err; + struct zt_context zt; + + /* ZA must be restored first for this check to be valid */ + if (!thread_za_enabled(¤t->thread)) + return -EINVAL; + + if (__copy_from_user(&zt, user->zt, sizeof(zt))) + return -EFAULT; + + if (zt.nregs != 1) + return -EINVAL; + + if (zt.head.size != ZT_SIG_CONTEXT_SIZE(zt.nregs)) + return -EINVAL; + + /* + * Careful: we are about __copy_from_user() directly into + * thread.zt_state with preemption enabled, so protection is + * needed to prevent a racing context switch from writing stale + * registers back over the new data. + */ + + fpsimd_flush_task_state(current); + /* From now, fpsimd_thread_switch() won't touch ZT in thread state */ + + err = __copy_from_user(thread_zt_state(¤t->thread), + (char __user const *)user->zt + + ZT_SIG_REGS_OFFSET, + ZT_SIG_REGS_SIZE(1)); + if (err) + return -EFAULT; + + return 0; +} + #else /* ! CONFIG_ARM64_SME */ /* Turn any non-optimised out attempts to use these into a link error: */ extern int preserve_za_context(void __user *ctx); extern int restore_za_context(struct user_ctxs *user); +extern int preserve_zt_context(void __user *ctx); +extern int restore_zt_context(struct user_ctxs *user); #endif /* ! CONFIG_ARM64_SME */ @@ -469,6 +541,7 @@ static int parse_user_sigframe(struct user_ctxs *user, user->fpsimd = NULL; user->sve = NULL; user->za = NULL; + user->zt = NULL; if (!IS_ALIGNED((unsigned long)base, 16)) goto invalid; @@ -547,6 +620,19 @@ static int parse_user_sigframe(struct user_ctxs *user, user->za = (struct za_context __user *)head; break; + case ZT_MAGIC: + if (!system_supports_sme2()) + goto invalid; + + if (user->zt) + goto invalid; + + if (size < sizeof(*user->zt)) + goto invalid; + + user->zt = (struct zt_context __user *)head; + break; + case EXTRA_MAGIC: if (have_extra_context) goto invalid; @@ -669,6 +755,9 @@ static int restore_sigframe(struct pt_regs *regs, if (err == 0 && system_supports_sme() && user.za) err = restore_za_context(&user); + if (err == 0 && system_supports_sme2() && user.zt) + err = restore_zt_context(&user); + return err; } @@ -769,6 +858,15 @@ static int setup_sigframe_layout(struct rt_sigframe_user_layout *user, return err; } + if (system_supports_sme2()) { + if (add_all || thread_za_enabled(¤t->thread)) { + err = sigframe_alloc(user, &user->zt_offset, + ZT_SIG_CONTEXT_SIZE(1)); + if (err) + return err; + } + } + return sigframe_alloc_end(user); } @@ -824,6 +922,13 @@ static int setup_sigframe(struct rt_sigframe_user_layout *user, err |= preserve_za_context(za_ctx); } + /* ZT state if present */ + if (system_supports_sme2() && err == 0 && user->zt_offset) { + struct zt_context __user *zt_ctx = + apply_user_offset(user, user->zt_offset); + err |= preserve_zt_context(zt_ctx); + } + if (err == 0 && user->extra_offset) { char __user *sfp = (char __user *)user->sigframe; char __user *userp = |