[v2,6/7] linux-user: Support SVE in aarch64 signal frames

Message ID 20180211205848.4568-7-richard.henderson@linaro.org
State New
Headers show
Series
  • target/arm: More SVE prep work
Related show

Commit Message

Richard Henderson Feb. 11, 2018, 8:58 p.m.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

---
 linux-user/signal.c | 348 ++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 283 insertions(+), 65 deletions(-)

-- 
2.14.3

Comments

Peter Maydell Feb. 15, 2018, 1:20 p.m. | #1
On 11 February 2018 at 20:58, Richard Henderson
<richard.henderson@linaro.org> wrote:
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

> ---

>  linux-user/signal.c | 348 ++++++++++++++++++++++++++++++++++++++++++----------

>  1 file changed, 283 insertions(+), 65 deletions(-)

>

> diff --git a/linux-user/signal.c b/linux-user/signal.c

> index 9a380b9e31..af953175db 100644

> --- a/linux-user/signal.c

> +++ b/linux-user/signal.c

> @@ -1443,35 +1443,61 @@ 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;

> +#define TARGET_EXTRA_MAGIC  0x45585401

> +

> +struct target_extra_context {

> +    struct target_aarch64_ctx head;

> +    uint64_t datap; /* 16-byte aligned pointer to extra space cast to __u64 */

> +    uint32_t size; /* size in bytes of the extra space */

> +    uint32_t reserved[3];

> +};

> +

> +#define TARGET_SVE_MAGIC    0x53564501

> +

> +struct target_sve_context {

> +    struct target_aarch64_ctx head;

> +    uint16_t vl;

> +    uint16_t reserved[3];

>  };


I found this patch too hard to review. It looks like you've combined
a refactoring of how we handle the AArch64 "bunch of extra auxiliary
context records" sigframe information with the addition of the SVE
context record. Could you split that into separate patches, please?
A description of why the current code isn't sufficient would also
be helpful.

thanks
-- PMM

Patch

diff --git a/linux-user/signal.c b/linux-user/signal.c
index 9a380b9e31..af953175db 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -1443,35 +1443,61 @@  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;
+#define TARGET_EXTRA_MAGIC  0x45585401
+
+struct target_extra_context {
+    struct target_aarch64_ctx head;
+    uint64_t datap; /* 16-byte aligned pointer to extra space cast to __u64 */
+    uint32_t size; /* size in bytes of the extra space */
+    uint32_t reserved[3];
+};
+
+#define TARGET_SVE_MAGIC    0x53564501
+
+struct target_sve_context {
+    struct target_aarch64_ctx head;
+    uint16_t vl;
+    uint16_t reserved[3];
 };
 
+#define TARGET_SVE_VQ_BYTES  16
+
+#define TARGET_SVE_SIG_ZREG_SIZE(VQ)  ((VQ) * TARGET_SVE_VQ_BYTES)
+#define TARGET_SVE_SIG_PREG_SIZE(VQ)  ((VQ) * (TARGET_SVE_VQ_BYTES / 8))
+
+#define TARGET_SVE_SIG_REGS_OFFSET \
+    QEMU_ALIGN_UP(sizeof(struct target_sve_context), TARGET_SVE_VQ_BYTES)
+#define TARGET_SVE_SIG_ZREG_OFFSET(VQ, N) \
+    (TARGET_SVE_SIG_REGS_OFFSET + TARGET_SVE_SIG_ZREG_SIZE(VQ) * (N))
+#define TARGET_SVE_SIG_PREG_OFFSET(VQ, N) \
+    (TARGET_SVE_SIG_ZREG_OFFSET(VQ, 32) + TARGET_SVE_SIG_PREG_SIZE(VQ) * (N))
+#define TARGET_SVE_SIG_FFR_OFFSET(VQ) \
+    (TARGET_SVE_SIG_PREG_OFFSET(VQ, 16))
+#define TARGET_SVE_SIG_CONTEXT_SIZE(VQ) \
+    (TARGET_SVE_SIG_PREG_OFFSET(VQ, 17))
+
 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];
 };
 
-static int target_setup_sigframe(struct target_rt_sigframe *sf,
-                                 CPUARMState *env, target_sigset_t *set)
+static void target_setup_general_frame(struct target_rt_sigframe *sf,
+                                       CPUARMState *env, target_sigset_t *set)
 {
     int i;
-    struct target_aux_context *aux =
-        (struct target_aux_context *)sf->uc.tuc_mcontext.__reserved;
 
-    /* set up the stack frame for unwinding */
-    __put_user(env->xregs[29], &sf->fp);
-    __put_user(env->xregs[30], &sf->lr);
+    __put_user(0, &sf->uc.tuc_flags);
+    __put_user(0, &sf->uc.tuc_link);
+
+    __put_user(target_sigaltstack_used.ss_sp, &sf->uc.tuc_stack.ss_sp);
+    __put_user(sas_ss_flags(env->xregs[31]), &sf->uc.tuc_stack.ss_flags);
+    __put_user(target_sigaltstack_used.ss_size, &sf->uc.tuc_stack.ss_size);
 
     for (i = 0; i < 31; i++) {
         __put_user(env->xregs[i], &sf->uc.tuc_mcontext.regs[i]);
@@ -1485,39 +1511,79 @@  static int target_setup_sigframe(struct target_rt_sigframe *sf,
     for (i = 0; i < TARGET_NSIG_WORDS; i++) {
         __put_user(set->sig[i], &sf->uc.tuc_sigmask.sig[i]);
     }
+}
+
+static void target_setup_end_record(struct target_aarch64_ctx *end)
+{
+    __put_user(0, &end->magic);
+    __put_user(0, &end->size);
+}
+
+static void target_setup_fpsimd_record(struct target_fpsimd_context *fpsimd,
+                                       CPUARMState *env)
+{
+    int i;
+
+    __put_user(TARGET_FPSIMD_MAGIC, &fpsimd->head.magic);
+    __put_user(sizeof(struct target_fpsimd_context), &fpsimd->head.size);
+    __put_user(vfp_get_fpsr(env), &fpsimd->fpsr);
+    __put_user(vfp_get_fpcr(env), &fpsimd->fpcr);
 
     for (i = 0; i < 32; i++) {
         uint64_t *q = aa64_vfp_qreg(env, i);
 #ifdef TARGET_WORDS_BIGENDIAN
-        __put_user(q[0], &aux->fpsimd.vregs[i * 2 + 1]);
-        __put_user(q[1], &aux->fpsimd.vregs[i * 2]);
+        __put_user(q[0], &fpsimd->vregs[i * 2 + 1]);
+        __put_user(q[1], &fpsimd->vregs[i * 2]);
 #else
-        __put_user(q[0], &aux->fpsimd.vregs[i * 2]);
-        __put_user(q[1], &aux->fpsimd.vregs[i * 2 + 1]);
+        __put_user(q[0], &fpsimd->vregs[i * 2]);
+        __put_user(q[1], &fpsimd->vregs[i * 2 + 1]);
 #endif
     }
-    __put_user(vfp_get_fpsr(env), &aux->fpsimd.fpsr);
-    __put_user(vfp_get_fpcr(env), &aux->fpsimd.fpcr);
-    __put_user(TARGET_FPSIMD_MAGIC, &aux->fpsimd.head.magic);
-    __put_user(sizeof(struct target_fpsimd_context),
-            &aux->fpsimd.head.size);
+}
 
-    /* set the "end" magic */
-    __put_user(0, &aux->end.magic);
-    __put_user(0, &aux->end.size);
+static void target_setup_extra_record(struct target_extra_context *extra,
+                                      uint64_t datap, uint32_t extra_size)
+{
+    __put_user(TARGET_EXTRA_MAGIC, &extra->head.magic);
+    __put_user(sizeof(struct target_extra_context), &extra->head.size);
+    __put_user(datap, &extra->datap);
+    __put_user(extra_size, &extra->size);
+}
 
-    return 0;
+static void target_setup_sve_record(struct target_sve_context *sve,
+                                    CPUARMState *env, int vq, int size)
+{
+    int i, j;
+
+    __put_user(TARGET_SVE_MAGIC, &sve->head.magic);
+    __put_user(size, &sve->head.size);
+    __put_user(vq * TARGET_SVE_VQ_BYTES, &sve->vl);
+
+    /* Note that SVE regs are stored as a byte stream, with each byte element
+     * at a subsequent address.  This corresponds to a little-endian store
+     * of our 64-bit hunks.
+     */
+    for (i = 0; i < 32; ++i) {
+        uint64_t *z = (void *)sve + TARGET_SVE_SIG_ZREG_OFFSET(vq, i);
+        for (j = 0; j < vq * 2; ++j) {
+            __put_user_e(env->vfp.zregs[i].d[j], z + j, le);
+        }
+    }
+    for (i = 0; i <= 16; ++i) {
+        uint16_t *p = (void *)sve + TARGET_SVE_SIG_PREG_OFFSET(vq, i);
+        for (j = 0; j < vq; ++j) {
+            uint64_t r = env->vfp.pregs[i].p[j >> 2];
+            __put_user_e(r >> ((j & 3) * 16), p + j, le);
+        }
+    }
 }
 
-static int target_restore_sigframe(CPUARMState *env,
-                                   struct target_rt_sigframe *sf)
+static void target_restore_general_frame(CPUARMState *env,
+                                         struct target_rt_sigframe *sf)
 {
     sigset_t set;
-    int i;
-    struct target_aux_context *aux =
-        (struct target_aux_context *)sf->uc.tuc_mcontext.__reserved;
-    uint32_t magic, size, fpsr, fpcr;
     uint64_t pstate;
+    int i;
 
     target_to_host_sigset(&set, &sf->uc.tuc_sigmask);
     set_sigmask(&set);
@@ -1530,34 +1596,134 @@  static int target_restore_sigframe(CPUARMState *env,
     __get_user(env->pc, &sf->uc.tuc_mcontext.pc);
     __get_user(pstate, &sf->uc.tuc_mcontext.pstate);
     pstate_write(env, pstate);
+}
 
-    __get_user(magic, &aux->fpsimd.head.magic);
-    __get_user(size, &aux->fpsimd.head.size);
+static void target_restore_fpsimd_record(CPUARMState *env,
+                                         struct target_fpsimd_context *fpsimd)
+{
+    uint32_t fpsr, fpcr;
+    int i;
 
-    if (magic != TARGET_FPSIMD_MAGIC
-        || size != sizeof(struct target_fpsimd_context)) {
-        return 1;
-    }
+    __get_user(fpsr, &fpsimd->fpsr);
+    vfp_set_fpsr(env, fpsr);
+    __get_user(fpcr, &fpsimd->fpcr);
+    vfp_set_fpcr(env, fpcr);
 
     for (i = 0; i < 32; i++) {
         uint64_t *q = aa64_vfp_qreg(env, i);
 #ifdef TARGET_WORDS_BIGENDIAN
-        __get_user(q[0], &aux->fpsimd.vregs[i * 2 + 1]);
-        __get_user(q[1], &aux->fpsimd.vregs[i * 2]);
+        __get_user(q[0], &fpsimd->vregs[i * 2 + 1]);
+        __get_user(q[1], &fpsimd->vregs[i * 2]);
 #else
-        __get_user(q[0], &aux->fpsimd.vregs[i * 2]);
-        __get_user(q[1], &aux->fpsimd.vregs[i * 2 + 1]);
+        __get_user(q[0], &fpsimd->vregs[i * 2]);
+        __get_user(q[1], &fpsimd->vregs[i * 2 + 1]);
 #endif
     }
-    __get_user(fpsr, &aux->fpsimd.fpsr);
-    vfp_set_fpsr(env, fpsr);
-    __get_user(fpcr, &aux->fpsimd.fpcr);
-    vfp_set_fpcr(env, fpcr);
+}
+
+static void target_restore_sve_record(CPUARMState *env,
+                                      struct target_sve_context *sve, int vq)
+{
+    int i, j;
+
+    /* Note that SVE regs are stored as a byte stream, with each byte element
+     * at a subsequent address.  This corresponds to a little-endian store
+     * of our 64-bit hunks.
+     */
+    for (i = 0; i < 32; ++i) {
+        uint64_t *z = (void *)sve + TARGET_SVE_SIG_ZREG_OFFSET(vq, i);
+        for (j = 0; j < vq * 2; ++j) {
+            __get_user_e(env->vfp.zregs[i].d[j], z + j, le);
+        }
+    }
+    for (i = 0; i <= 16; ++i) {
+        uint16_t *p = (void *)sve + TARGET_SVE_SIG_PREG_OFFSET(vq, i);
+        for (j = 0; j < vq; ++j) {
+            uint16_t r;
+            __get_user_e(r, p + j, le);
+            if (j & 3) {
+                env->vfp.pregs[i].p[j >> 2] |= (uint64_t)r << ((j & 3) * 16);
+            } else {
+                env->vfp.pregs[i].p[j >> 2] = r;
+            }
+        }
+    }
+}
+
+static int target_restore_sigframe(CPUARMState *env,
+                                   struct target_rt_sigframe *sf)
+{
+    struct target_aarch64_ctx *ctx, *extra = NULL;
+    struct target_fpsimd_context *fpsimd = NULL;
+    struct target_sve_context *sve = NULL;
+    int vq = 0, sve_size = 0;
+
+    target_restore_general_frame(env, sf);
+
+    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 TARGET_FPSIMD_MAGIC:
+            if (fpsimd || size != sizeof(struct target_fpsimd_context)) {
+                return 1;
+            }
+            fpsimd = (struct target_fpsimd_context *)ctx;
+            break;
+
+        case TARGET_SVE_MAGIC:
+            if (arm_feature(env, ARM_FEATURE_SVE)) {
+                vq = (env->vfp.zcr_el[1] & 0xf) + 1;
+                sve_size = QEMU_ALIGN_UP(TARGET_SVE_SIG_CONTEXT_SIZE(vq), 16);
+                if (!sve && size == sve_size) {
+                    sve = (struct target_sve_context *)ctx;
+                    break;
+                }
+            }
+            return 1;
+
+        case TARGET_EXTRA_MAGIC:
+            if (size != sizeof(struct target_extra_context)) {
+                return 1;
+            }
+            extra = (void *)((struct target_extra_context *)ctx)->datap;
+            break;
+
+        default:
+            /* Unknown record -- we certainly didn't generate it.
+               Did we in fact get out of sync?  */
+            return 1;
+
+        case 0:
+            if (size != 0) {
+                return 1;
+            }
+            ctx = extra;
+            extra = NULL;
+            continue;
+        }
+        ctx = (void *)ctx + size;
+    }
+
+    /* Require FPSIMD always, since we always restore FPSR/FPCR from there.  */
+    if (!fpsimd) {
+        return 1;
+    }
+    target_restore_fpsimd_record(env, fpsimd);
+
+    /* SVE data, if present, overwrites FPSIMD data.  */
+    if (sve) {
+        target_restore_sve_record(env, sve, vq);
+    }
 
     return 0;
 }
 
-static abi_ulong get_sigframe(struct target_sigaction *ka, CPUARMState *env)
+static abi_ulong get_sigframe(struct target_sigaction *ka,
+                              CPUARMState *env, int size)
 {
     abi_ulong sp;
 
@@ -1570,7 +1736,7 @@  static abi_ulong get_sigframe(struct target_sigaction *ka, CPUARMState *env)
         sp = target_sigaltstack_used.ss_sp + target_sigaltstack_used.ss_size;
     }
 
-    sp = (sp - sizeof(struct target_rt_sigframe)) & ~15;
+    sp = (sp - size) & ~15;
 
     return sp;
 }
@@ -1579,25 +1745,76 @@  static void target_setup_frame(int usig, struct target_sigaction *ka,
                                target_siginfo_t *info, target_sigset_t *set,
                                CPUARMState *env)
 {
+    int std_size = sizeof(struct target_rt_sigframe);
+    int size = offsetof(struct target_rt_sigframe, uc.tuc_mcontext.__reserved);
+    int fpsimd_ofs, end1_ofs, fr_ofs;
+    int sve_ofs = 0, extra_ofs = 0, end2_ofs = 0;
+    int vq = 0, sve_size = 0, extra_size = 0;
     struct target_rt_sigframe *frame;
+    struct target_rt_frame_record *fr;
     abi_ulong frame_addr, return_addr;
 
-    frame_addr = get_sigframe(ka, env);
+    /* Reserve space for standard exit marker.  */
+    std_size -= sizeof(struct target_aarch64_ctx);
+
+    /* FPSIMD record is always in the standard space.  */
+    fpsimd_ofs = size;
+    size += sizeof(struct target_fpsimd_context);
+    end1_ofs = size;
+
+    /* SVE state needs saving only if it exists.  */
+    if (arm_feature(env, ARM_FEATURE_SVE)) {
+        vq = (env->vfp.zcr_el[1] & 0xf) + 1;
+        sve_size = QEMU_ALIGN_UP(TARGET_SVE_SIG_CONTEXT_SIZE(vq), 16);
+
+        /* For VQ <= 6, there is room in the standard space.  */
+        if (sve_size <= std_size) {
+            sve_ofs = size;
+            size += sve_size;
+            end1_ofs = size;
+        } else {
+            /* Otherwise we need to allocate extra space.  */
+            extra_ofs = size;
+            size += sizeof(struct target_extra_context);
+            end1_ofs = size;
+            size += QEMU_ALIGN_UP(sizeof(struct target_aarch64_ctx), 16);
+
+            extra_size = sve_size + sizeof(struct target_aarch64_ctx);
+            sve_ofs = size;
+            size += sve_size;
+            end2_ofs = size;
+        }
+    }
+    size += sizeof(struct target_aarch64_ctx);
+
+    fr_ofs = size;
+    size += sizeof(struct target_rt_frame_record);
+
+    frame_addr = get_sigframe(ka, env, size);
     trace_user_setup_frame(env, frame_addr);
     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
         goto give_sigsegv;
     }
 
-    __put_user(0, &frame->uc.tuc_flags);
-    __put_user(0, &frame->uc.tuc_link);
+    target_setup_general_frame(frame, env, set);
+    target_setup_fpsimd_record((void *)frame + fpsimd_ofs, env);
+    if (extra_ofs) {
+        target_setup_extra_record((void *)frame + extra_ofs,
+                                  frame_addr + sve_ofs, extra_size);
+    }
+    target_setup_end_record((void *)frame + end1_ofs);
+    if (sve_ofs) {
+        target_setup_sve_record((void *)frame + sve_ofs, env, vq, sve_size);
+    }
+    if (end2_ofs) {
+        target_setup_end_record((void *)frame + end2_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);
 
-    __put_user(target_sigaltstack_used.ss_sp,
-                      &frame->uc.tuc_stack.ss_sp);
-    __put_user(sas_ss_flags(env->xregs[31]),
-                      &frame->uc.tuc_stack.ss_flags);
-    __put_user(target_sigaltstack_used.ss_size,
-                      &frame->uc.tuc_stack.ss_size);
-    target_setup_sigframe(frame, env, set);
     if (ka->sa_flags & TARGET_SA_RESTORER) {
         return_addr = ka->sa_restorer;
     } else {
@@ -1606,13 +1823,14 @@  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) {