diff mbox series

[v4,21/57] tcg/i386: Use full load/store helpers in user-only mode

Message ID 20230503070656.1746170-22-richard.henderson@linaro.org
State Superseded
Headers show
Series tcg: Improve atomicity support | expand

Commit Message

Richard Henderson May 3, 2023, 7:06 a.m. UTC 
Instead of using helper_unaligned_{ld,st}, use the full load/store helpers.
This will allow the fast path to increase alignment to implement atomicity
while not immediately raising an alignment exception.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/i386/tcg-target.c.inc | 52 +++------------------------------------
 1 file changed, 4 insertions(+), 48 deletions(-)

Comments

Peter Maydell May 5, 2023, 12:01 p.m. UTC | #1 
On Wed, 3 May 2023 at 08:09, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> Instead of using helper_unaligned_{ld,st}, use the full load/store helpers.
> This will allow the fast path to increase alignment to implement atomicity
> while not immediately raising an alignment exception.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM
diff mbox series

Patch

diff --git a/tcg/i386/tcg-target.c.inc b/tcg/i386/tcg-target.c.inc
index f838683fc3..e78d4d4aa7 100644
--- a/tcg/i386/tcg-target.c.inc
+++ b/tcg/i386/tcg-target.c.inc
@@ -1776,7 +1776,6 @@  typedef struct {
     int seg;
 } HostAddress;
 
-#if defined(CONFIG_SOFTMMU)
 /*
  * Because i686 has no register parameters and because x86_64 has xchg
  * to handle addr/data register overlap, we have placed all input arguments
@@ -1812,7 +1811,7 @@  static bool tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *l)
 
     /* resolve label address */
     tcg_patch32(label_ptr[0], s->code_ptr - label_ptr[0] - 4);
-    if (TARGET_LONG_BITS > TCG_TARGET_REG_BITS) {
+    if (label_ptr[1]) {
         tcg_patch32(label_ptr[1], s->code_ptr - label_ptr[1] - 4);
     }
 
@@ -1834,7 +1833,7 @@  static bool tcg_out_qemu_st_slow_path(TCGContext *s, TCGLabelQemuLdst *l)
 
     /* resolve label address */
     tcg_patch32(label_ptr[0], s->code_ptr - label_ptr[0] - 4);
-    if (TARGET_LONG_BITS > TCG_TARGET_REG_BITS) {
+    if (label_ptr[1]) {
         tcg_patch32(label_ptr[1], s->code_ptr - label_ptr[1] - 4);
     }
 
@@ -1844,51 +1843,8 @@  static bool tcg_out_qemu_st_slow_path(TCGContext *s, TCGLabelQemuLdst *l)
     tcg_out_jmp(s, l->raddr);
     return true;
 }
-#else
-static bool tcg_out_fail_alignment(TCGContext *s, TCGLabelQemuLdst *l)
-{
-    /* resolve label address */
-    tcg_patch32(l->label_ptr[0], s->code_ptr - l->label_ptr[0] - 4);
-
-    if (TCG_TARGET_REG_BITS == 32) {
-        int ofs = 0;
-
-        tcg_out_st(s, TCG_TYPE_PTR, TCG_AREG0, TCG_REG_ESP, ofs);
-        ofs += 4;
-
-        tcg_out_st(s, TCG_TYPE_I32, l->addrlo_reg, TCG_REG_ESP, ofs);
-        ofs += 4;
-        if (TARGET_LONG_BITS == 64) {
-            tcg_out_st(s, TCG_TYPE_I32, l->addrhi_reg, TCG_REG_ESP, ofs);
-            ofs += 4;
-        }
-
-        tcg_out_pushi(s, (uintptr_t)l->raddr);
-    } else {
-        tcg_out_mov(s, TCG_TYPE_TL, tcg_target_call_iarg_regs[1],
-                    l->addrlo_reg);
-        tcg_out_mov(s, TCG_TYPE_PTR, tcg_target_call_iarg_regs[0], TCG_AREG0);
-
-        tcg_out_movi(s, TCG_TYPE_PTR, TCG_REG_RAX, (uintptr_t)l->raddr);
-        tcg_out_push(s, TCG_REG_RAX);
-    }
-
-    /* "Tail call" to the helper, with the return address back inline. */
-    tcg_out_jmp(s, (const void *)(l->is_ld ? helper_unaligned_ld
-                                  : helper_unaligned_st));
-    return true;
-}
-
-static bool tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *l)
-{
-    return tcg_out_fail_alignment(s, l);
-}
-
-static bool tcg_out_qemu_st_slow_path(TCGContext *s, TCGLabelQemuLdst *l)
-{
-    return tcg_out_fail_alignment(s, l);
-}
 
+#ifndef CONFIG_SOFTMMU
 static HostAddress x86_guest_base = {
     .index = -1
 };
@@ -1920,7 +1876,7 @@  static inline int setup_guest_base_seg(void)
     return 0;
 }
 #endif /* setup_guest_base_seg */
-#endif /* SOFTMMU */
+#endif /* !SOFTMMU */
 
 /*
  * For softmmu, perform the TLB load and compare.