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Re: [Qemu-devel] [PATCH v4 3/5] aarch64-linux-user: Remove struct target
From: |
Alex Bennée |
Subject: |
Re: [Qemu-devel] [PATCH v4 3/5] aarch64-linux-user: Remove struct target_aux_context |
Date: |
Tue, 06 Mar 2018 14:16:22 +0000 |
User-agent: |
mu4e 1.1.0; emacs 26.0.91 |
Richard Henderson <address@hidden> writes:
> This changes the qemu signal frame layout to be more like the kernel's,
> in that the various records are dynamically allocated rather than fixed
> in place by a structure.
>
> For now, all of the allocation is out of uc.tuc_mcontext.__reserved,
> so the allocation is actually trivial. That will change with SVE support.
>
> Reviewed-by: Peter Maydell <address@hidden>
> Signed-off-by: Richard Henderson <address@hidden>
Reviewed-by: Alex Bennée <address@hidden>
> ---
> linux-user/signal.c | 89
> ++++++++++++++++++++++++++++++++++++-----------------
> 1 file changed, 61 insertions(+), 28 deletions(-)
>
> diff --git a/linux-user/signal.c b/linux-user/signal.c
> index 25c9743aed..f9eef3d753 100644
> --- a/linux-user/signal.c
> +++ b/linux-user/signal.c
> @@ -1443,20 +1443,12 @@ struct target_fpsimd_context {
> uint64_t vregs[32 * 2]; /* really uint128_t vregs[32] */
> };
>
> -/*
> - * Auxiliary context saved in the sigcontext.__reserved array. Not exported
> to
> - * user space as it will change with the addition of new context. User space
> - * should check the magic/size information.
> - */
> -struct target_aux_context {
> - struct target_fpsimd_context fpsimd;
> - /* additional context to be added before "end" */
> - struct target_aarch64_ctx end;
> -};
> -
> struct target_rt_sigframe {
> struct target_siginfo info;
> struct target_ucontext uc;
> +};
> +
> +struct target_rt_frame_record {
> uint64_t fp;
> uint64_t lr;
> uint32_t tramp[2];
> @@ -1562,20 +1554,47 @@ static void target_restore_fpsimd_record(CPUARMState
> *env,
> static int target_restore_sigframe(CPUARMState *env,
> struct target_rt_sigframe *sf)
> {
> - struct target_aux_context *aux
> - = (struct target_aux_context *)sf->uc.tuc_mcontext.__reserved;
> - uint32_t magic, size;
> + struct target_aarch64_ctx *ctx;
> + struct target_fpsimd_context *fpsimd = NULL;
>
> target_restore_general_frame(env, sf);
>
> - __get_user(magic, &aux->fpsimd.head.magic);
> - __get_user(size, &aux->fpsimd.head.size);
> - if (magic == TARGET_FPSIMD_MAGIC
> - && size == sizeof(struct target_fpsimd_context)) {
> - target_restore_fpsimd_record(env, &aux->fpsimd);
> - } else {
> + ctx = (struct target_aarch64_ctx *)sf->uc.tuc_mcontext.__reserved;
> + while (ctx) {
> + uint32_t magic, size;
> +
> + __get_user(magic, &ctx->magic);
> + __get_user(size, &ctx->size);
> + switch (magic) {
> + case 0:
> + if (size != 0) {
> + return 1;
> + }
> + ctx = NULL;
> + continue;
> +
> + case TARGET_FPSIMD_MAGIC:
> + if (fpsimd || size != sizeof(struct target_fpsimd_context)) {
> + return 1;
> + }
> + fpsimd = (struct target_fpsimd_context *)ctx;
> + break;
> +
> + default:
> + /* Unknown record -- we certainly didn't generate it.
> + * Did we in fact get out of sync?
> + */
> + return 1;
> + }
> + ctx = (void *)ctx + size;
> + }
> +
> + /* Require FPSIMD always. */
> + if (!fpsimd) {
> return 1;
> }
> + target_restore_fpsimd_record(env, fpsimd);
> +
> return 0;
> }
>
> @@ -1601,20 +1620,33 @@ static void target_setup_frame(int usig, struct
> target_sigaction *ka,
> target_siginfo_t *info, target_sigset_t *set,
> CPUARMState *env)
> {
> + int size = offsetof(struct target_rt_sigframe,
> uc.tuc_mcontext.__reserved);
> + int fpsimd_ofs, end1_ofs, fr_ofs;
> struct target_rt_sigframe *frame;
> - struct target_aux_context *aux;
> + struct target_rt_frame_record *fr;
> abi_ulong frame_addr, return_addr;
>
> + fpsimd_ofs = size;
> + size += sizeof(struct target_fpsimd_context);
> + end1_ofs = size;
> + size += sizeof(struct target_aarch64_ctx);
> + fr_ofs = size;
> + size += sizeof(struct target_rt_frame_record);
> +
> frame_addr = get_sigframe(ka, env);
> trace_user_setup_frame(env, frame_addr);
> if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
> goto give_sigsegv;
> }
> - aux = (struct target_aux_context *)frame->uc.tuc_mcontext.__reserved;
>
> target_setup_general_frame(frame, env, set);
> - target_setup_fpsimd_record(&aux->fpsimd, env);
> - target_setup_end_record(&aux->end);
> + target_setup_fpsimd_record((void *)frame + fpsimd_ofs, env);
> + target_setup_end_record((void *)frame + end1_ofs);
> +
> + /* Set up the stack frame for unwinding. */
> + fr = (void *)frame + fr_ofs;
> + __put_user(env->xregs[29], &fr->fp);
> + __put_user(env->xregs[30], &fr->lr);
>
> if (ka->sa_flags & TARGET_SA_RESTORER) {
> return_addr = ka->sa_restorer;
> @@ -1624,13 +1656,14 @@ static void target_setup_frame(int usig, struct
> target_sigaction *ka,
> * Since these are instructions they need to be put as little-endian
> * regardless of target default or current CPU endianness.
> */
> - __put_user_e(0xd2801168, &frame->tramp[0], le);
> - __put_user_e(0xd4000001, &frame->tramp[1], le);
> - return_addr = frame_addr + offsetof(struct target_rt_sigframe,
> tramp);
> + __put_user_e(0xd2801168, &fr->tramp[0], le);
> + __put_user_e(0xd4000001, &fr->tramp[1], le);
> + return_addr = frame_addr + fr_ofs
> + + offsetof(struct target_rt_frame_record, tramp);
> }
> env->xregs[0] = usig;
> env->xregs[31] = frame_addr;
> - env->xregs[29] = env->xregs[31] + offsetof(struct target_rt_sigframe,
> fp);
> + env->xregs[29] = frame_addr + fr_ofs;
> env->pc = ka->_sa_handler;
> env->xregs[30] = return_addr;
> if (info) {
--
Alex Bennée
- [Qemu-devel] [PATCH v4 0/5] target/arm linux-user changes for sve, Richard Henderson, 2018/03/03
- [Qemu-devel] [PATCH v4 2/5] aarch64-linux-user: Split out helpers for guest signal handling, Richard Henderson, 2018/03/03
- [Qemu-devel] [PATCH v4 3/5] aarch64-linux-user: Remove struct target_aux_context, Richard Henderson, 2018/03/03
- Re: [Qemu-devel] [PATCH v4 3/5] aarch64-linux-user: Remove struct target_aux_context,
Alex Bennée <=
- [Qemu-devel] [PATCH v4 4/5] aarch64-linux-user: Add support for EXTRA signal frame records, Richard Henderson, 2018/03/03
- [Qemu-devel] [PATCH v4 5/5] aarch64-linux-user: Add support for SVE signal frame records, Richard Henderson, 2018/03/03
- Re: [Qemu-devel] [PATCH v4 0/5] target/arm linux-user changes for sve, Peter Maydell, 2018/03/05