From 270de609ae2af441d15289406340ff209e5dc864 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Tue, 6 Feb 2024 12:38:46 +0000 Subject: arm64: Simplify do_notify_resume() DAIF masking In do_notify_resume, we handle _TIF_NEED_RESCHED differently from all other flags, leaving IRQ+FIQ masked when calling into schedule(). This masking is a historical artifact, and it is not currently necessary to mask IRQ+FIQ when calling into schedule (as evidenced by the generic exit_to_user_mode_loop(), which unmasks IRQs before checking _TIF_NEED_RESCHED and calling schedule()). This patch removes the special case for _TIF_NEED_RESCHED, moving this check into the main loop such that schedule() will be called from a regular process context with IRQ+FIQ unmasked. This is a minor simplification to do_notify_resume() and brings it into line with the generic exit_to_user_mode_loop() logic. This will also aid subsequent rework of DAIF management. Signed-off-by: Mark Rutland Cc: James Morse Cc: Mark Brown Cc: Will Deacon Reviewed-by: Mark Brown Link: https://lore.kernel.org/r/20240206123848.1696480-2-mark.rutland@arm.com Signed-off-by: Catalin Marinas Tested-by: Itaru Kitayama --- arch/arm64/kernel/signal.c | 34 +++++++++++++++------------------- 1 file changed, 15 insertions(+), 19 deletions(-) (limited to 'arch/arm64/kernel/signal.c') diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 0e8beb3349ea..50e108741599 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -1281,32 +1281,28 @@ static void do_signal(struct pt_regs *regs) void do_notify_resume(struct pt_regs *regs, unsigned long thread_flags) { do { - if (thread_flags & _TIF_NEED_RESCHED) { - /* Unmask Debug and SError for the next task */ - local_daif_restore(DAIF_PROCCTX_NOIRQ); + local_daif_restore(DAIF_PROCCTX); + if (thread_flags & _TIF_NEED_RESCHED) schedule(); - } else { - local_daif_restore(DAIF_PROCCTX); - if (thread_flags & _TIF_UPROBE) - uprobe_notify_resume(regs); + if (thread_flags & _TIF_UPROBE) + uprobe_notify_resume(regs); - if (thread_flags & _TIF_MTE_ASYNC_FAULT) { - clear_thread_flag(TIF_MTE_ASYNC_FAULT); - send_sig_fault(SIGSEGV, SEGV_MTEAERR, - (void __user *)NULL, current); - } + if (thread_flags & _TIF_MTE_ASYNC_FAULT) { + clear_thread_flag(TIF_MTE_ASYNC_FAULT); + send_sig_fault(SIGSEGV, SEGV_MTEAERR, + (void __user *)NULL, current); + } - if (thread_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) - do_signal(regs); + if (thread_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) + do_signal(regs); - if (thread_flags & _TIF_NOTIFY_RESUME) - resume_user_mode_work(regs); + if (thread_flags & _TIF_NOTIFY_RESUME) + resume_user_mode_work(regs); - if (thread_flags & _TIF_FOREIGN_FPSTATE) - fpsimd_restore_current_state(); - } + if (thread_flags & _TIF_FOREIGN_FPSTATE) + fpsimd_restore_current_state(); local_daif_mask(); thread_flags = read_thread_flags(); -- cgit From 997d79eb938e981ab0d3714d39ed148bce131d9e Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Tue, 6 Feb 2024 12:38:47 +0000 Subject: arm64: Move do_notify_resume() to entry-common.c Currently do_notify_resume() lives in arch/arm64/kernel/signal.c, but it would make more sense for it to live in entry-common.c as it handles more than signals, and is coupled with the rest of the return-to-userspace sequence (e.g. with unusual DAIF masking that matches the exception return requirements). Move do_notify_resume() to entry-common.c. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland Cc: James Morse Cc: Mark Brown Cc: Will Deacon Reviewed-by: Mark Brown Link: https://lore.kernel.org/r/20240206123848.1696480-3-mark.rutland@arm.com Signed-off-by: Catalin Marinas Tested-by: Itaru Kitayama --- arch/arm64/kernel/signal.c | 35 ++--------------------------------- 1 file changed, 2 insertions(+), 33 deletions(-) (limited to 'arch/arm64/kernel/signal.c') diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 50e108741599..c08e6465e0f4 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -16,8 +16,8 @@ #include #include #include -#include #include +#include #include #include @@ -1207,7 +1207,7 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) * the kernel can handle, and then we build all the user-level signal handling * stack-frames in one go after that. */ -static void do_signal(struct pt_regs *regs) +void do_signal(struct pt_regs *regs) { unsigned long continue_addr = 0, restart_addr = 0; int retval = 0; @@ -1278,37 +1278,6 @@ static void do_signal(struct pt_regs *regs) restore_saved_sigmask(); } -void do_notify_resume(struct pt_regs *regs, unsigned long thread_flags) -{ - do { - local_daif_restore(DAIF_PROCCTX); - - if (thread_flags & _TIF_NEED_RESCHED) - schedule(); - - if (thread_flags & _TIF_UPROBE) - uprobe_notify_resume(regs); - - if (thread_flags & _TIF_MTE_ASYNC_FAULT) { - clear_thread_flag(TIF_MTE_ASYNC_FAULT); - send_sig_fault(SIGSEGV, SEGV_MTEAERR, - (void __user *)NULL, current); - } - - if (thread_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) - do_signal(regs); - - if (thread_flags & _TIF_NOTIFY_RESUME) - resume_user_mode_work(regs); - - if (thread_flags & _TIF_FOREIGN_FPSTATE) - fpsimd_restore_current_state(); - - local_daif_mask(); - thread_flags = read_thread_flags(); - } while (thread_flags & _TIF_WORK_MASK); -} - unsigned long __ro_after_init signal_minsigstksz; /* -- cgit From 8c46def44409fc914278630b7ba5ac142ab7c4f4 Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Wed, 6 Mar 2024 23:14:49 +0000 Subject: arm64/signal: Add FPMR signal handling Expose FPMR in the signal context on systems where it is supported. The kernel validates the exact size of the FPSIMD registers so we can't readily add it to fpsimd_context without disruption. Signed-off-by: Mark Brown Link: https://lore.kernel.org/r/20240306-arm64-2023-dpisa-v5-4-c568edc8ed7f@kernel.org Signed-off-by: Catalin Marinas --- arch/arm64/kernel/signal.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) (limited to 'arch/arm64/kernel/signal.c') diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 0e8beb3349ea..460823baa603 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -60,6 +60,7 @@ struct rt_sigframe_user_layout { unsigned long tpidr2_offset; unsigned long za_offset; unsigned long zt_offset; + unsigned long fpmr_offset; unsigned long extra_offset; unsigned long end_offset; }; @@ -182,6 +183,8 @@ struct user_ctxs { u32 za_size; struct zt_context __user *zt; u32 zt_size; + struct fpmr_context __user *fpmr; + u32 fpmr_size; }; static int preserve_fpsimd_context(struct fpsimd_context __user *ctx) @@ -227,6 +230,33 @@ static int restore_fpsimd_context(struct user_ctxs *user) return err ? -EFAULT : 0; } +static int preserve_fpmr_context(struct fpmr_context __user *ctx) +{ + int err = 0; + + current->thread.uw.fpmr = read_sysreg_s(SYS_FPMR); + + __put_user_error(FPMR_MAGIC, &ctx->head.magic, err); + __put_user_error(sizeof(*ctx), &ctx->head.size, err); + __put_user_error(current->thread.uw.fpmr, &ctx->fpmr, err); + + return err; +} + +static int restore_fpmr_context(struct user_ctxs *user) +{ + u64 fpmr; + int err = 0; + + if (user->fpmr_size != sizeof(*user->fpmr)) + return -EINVAL; + + __get_user_error(fpmr, &user->fpmr->fpmr, err); + if (!err) + write_sysreg_s(fpmr, SYS_FPMR); + + return err; +} #ifdef CONFIG_ARM64_SVE @@ -590,6 +620,7 @@ static int parse_user_sigframe(struct user_ctxs *user, user->tpidr2 = NULL; user->za = NULL; user->zt = NULL; + user->fpmr = NULL; if (!IS_ALIGNED((unsigned long)base, 16)) goto invalid; @@ -684,6 +715,17 @@ static int parse_user_sigframe(struct user_ctxs *user, user->zt_size = size; break; + case FPMR_MAGIC: + if (!system_supports_fpmr()) + goto invalid; + + if (user->fpmr) + goto invalid; + + user->fpmr = (struct fpmr_context __user *)head; + user->fpmr_size = size; + break; + case EXTRA_MAGIC: if (have_extra_context) goto invalid; @@ -806,6 +848,9 @@ static int restore_sigframe(struct pt_regs *regs, if (err == 0 && system_supports_tpidr2() && user.tpidr2) err = restore_tpidr2_context(&user); + if (err == 0 && system_supports_fpmr() && user.fpmr) + err = restore_fpmr_context(&user); + if (err == 0 && system_supports_sme() && user.za) err = restore_za_context(&user); @@ -928,6 +973,13 @@ static int setup_sigframe_layout(struct rt_sigframe_user_layout *user, } } + if (system_supports_fpmr()) { + err = sigframe_alloc(user, &user->fpmr_offset, + sizeof(struct fpmr_context)); + if (err) + return err; + } + return sigframe_alloc_end(user); } @@ -983,6 +1035,13 @@ static int setup_sigframe(struct rt_sigframe_user_layout *user, err |= preserve_tpidr2_context(tpidr2_ctx); } + /* FPMR if supported */ + if (system_supports_fpmr() && err == 0) { + struct fpmr_context __user *fpmr_ctx = + apply_user_offset(user, user->fpmr_offset); + err |= preserve_fpmr_context(fpmr_ctx); + } + /* ZA state if present */ if (system_supports_sme() && err == 0 && user->za_offset) { struct za_context __user *za_ctx = -- cgit