aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorRichard Henderson <rth@twiddle.net>2013-08-27 10:22:54 -0700
committerRichard Henderson <rth@twiddle.net>2013-09-02 09:08:30 -0700
commit0f842f8a246f2b5b51a11c13f933bf7a90ae8e96 (patch)
tree2dd695c689fb49d15fe28f2792fde11dba5be55e
parentc72b26ec92eb93a92852ab1d23acb5a945de5062 (diff)
downloadqemu-arm-0f842f8a246f2b5b51a11c13f933bf7a90ae8e96.tar.gz
exec: Reorganize the GETRA/GETPC macros
Always define GETRA; use __builtin_extract_return_addr, rather than having a special case for s390. Split GETPC_ADJ out of GETPC; use 2 universally, rather than having a special case for arm. Rename GETPC_LDST to GETRA_LDST to indicate that it does not contain the GETPC_ADJ value. Likewise with GETPC_EXT to GETRA_EXT. Perform the GETPC_ADJ adjustment inside helper_ret_ld/st. This will allow backends to pass along the "true" return address rather than the massaged GETPC value. In the meantime, double application of GETPC_ADJ does not hurt, since the call insn in all ISAs is at least 4 bytes long. Reviewed-by: Aurelien Jarno <aurelien@aurel32.net> Signed-off-by: Richard Henderson <rth@twiddle.net>
-rw-r--r--include/exec/exec-all.h84
-rw-r--r--include/exec/softmmu_template.h24
2 files changed, 56 insertions, 52 deletions
diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index ffb69a4c70..6f71a4fdae 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -295,47 +295,42 @@ static inline void tb_add_jump(TranslationBlock *tb, int n,
}
}
-/* The return address may point to the start of the next instruction.
- Subtracting one gets us the call instruction itself. */
+/* GETRA is the true target of the return instruction that we'll execute,
+ defined here for simplicity of defining the follow-up macros. */
#if defined(CONFIG_TCG_INTERPRETER)
extern uintptr_t tci_tb_ptr;
-# define GETPC() tci_tb_ptr
-#elif defined(__s390__) && !defined(__s390x__)
-# define GETPC() \
- (((uintptr_t)__builtin_return_address(0) & 0x7fffffffUL) - 1)
-#elif defined(__arm__)
-/* Thumb return addresses have the low bit set, so we need to subtract two.
- This is still safe in ARM mode because instructions are 4 bytes. */
-# define GETPC() ((uintptr_t)__builtin_return_address(0) - 2)
+# define GETRA() tci_tb_ptr
+#else
+# define GETRA() \
+ ((uintptr_t)__builtin_extract_return_addr(__builtin_return_address(0)))
+#endif
+
+/* The true return address will often point to a host insn that is part of
+ the next translated guest insn. Adjust the address backward to point to
+ the middle of the call insn. Subtracting one would do the job except for
+ several compressed mode architectures (arm, mips) which set the low bit
+ to indicate the compressed mode; subtracting two works around that. It
+ is also the case that there are no host isas that contain a call insn
+ smaller than 4 bytes, so we don't worry about special-casing this. */
+#if defined(CONFIG_TCG_INTERPRETER)
+# define GETPC_ADJ 0
#else
-# define GETPC() ((uintptr_t)__builtin_return_address(0) - 1)
+# define GETPC_ADJ 2
#endif
+#define GETPC() (GETRA() - GETPC_ADJ)
+
+/* The LDST optimizations splits code generation into fast and slow path.
+ In some implementations, we pass the "logical" return address manually;
+ in others, we must infer the logical return from the true return. */
#if defined(CONFIG_QEMU_LDST_OPTIMIZATION) && defined(CONFIG_SOFTMMU)
-/* qemu_ld/st optimization split code generation to fast and slow path, thus,
- it needs special handling for an MMU helper which is called from the slow
- path, to get the fast path's pc without any additional argument.
- It uses a tricky solution which embeds the fast path pc into the slow path.
-
- Code flow in slow path:
- (1) pre-process
- (2) call MMU helper
- (3) jump to (5)
- (4) fast path information (implementation specific)
- (5) post-process (e.g. stack adjust)
- (6) jump to corresponding code of the next of fast path
- */
-# if defined(__i386__) || defined(__x86_64__)
-# define GETPC_EXT() GETPC()
-# elif defined (_ARCH_PPC) && !defined (_ARCH_PPC64)
-# define GETRA() ((uintptr_t)__builtin_return_address(0))
-# define GETPC_LDST() ((uintptr_t) ((*(int32_t *)(GETRA() - 4)) - 1))
+# if defined (_ARCH_PPC) && !defined (_ARCH_PPC64)
+# define GETRA_LDST(RA) (*(int32_t *)((RA) - 4))
# elif defined(__arm__)
/* We define two insns between the return address and the branch back to
straight-line. Find and decode that branch insn. */
-# define GETRA() ((uintptr_t)__builtin_return_address(0))
-# define GETPC_LDST() tcg_getpc_ldst(GETRA())
-static inline uintptr_t tcg_getpc_ldst(uintptr_t ra)
+# define GETRA_LDST(RA) tcg_getra_ldst(RA)
+static inline uintptr_t tcg_getra_ldst(uintptr_t ra)
{
int32_t b;
ra += 8; /* skip the two insns */
@@ -343,33 +338,32 @@ static inline uintptr_t tcg_getpc_ldst(uintptr_t ra)
b = (b << 8) >> (8 - 2); /* extract the displacement */
ra += 8; /* branches are relative to pc+8 */
ra += b; /* apply the displacement */
- ra -= 4; /* return a pointer into the current opcode,
- not the start of the next opcode */
return ra;
}
# elif defined(__aarch64__)
-# define GETRA() ((uintptr_t)__builtin_return_address(0))
-# define GETPC_LDST() tcg_getpc_ldst(GETRA())
-static inline uintptr_t tcg_getpc_ldst(uintptr_t ra)
+# define GETRA_LDST(RA) tcg_getra_ldst(RA)
+static inline uintptr_t tcg_getra_ldst(uintptr_t ra)
{
int32_t b;
ra += 4; /* skip one instruction */
b = *(int32_t *)ra; /* load the branch insn */
b = (b << 6) >> (6 - 2); /* extract the displacement */
ra += b; /* apply the displacement */
- ra -= 4; /* return a pointer into the current opcode,
- not the start of the next opcode */
return ra;
}
-# else
-# error "CONFIG_QEMU_LDST_OPTIMIZATION needs GETPC_LDST() implementation!"
# endif
+#endif /* CONFIG_QEMU_LDST_OPTIMIZATION */
+
+/* ??? Delete these once they are no longer used. */
bool is_tcg_gen_code(uintptr_t pc_ptr);
-# ifndef GETPC_EXT
-# define GETPC_EXT() (is_tcg_gen_code(GETRA()) ? GETPC_LDST() : GETPC())
-# endif
+#ifdef GETRA_LDST
+# define GETRA_EXT() tcg_getra_ext(GETRA())
+static inline uintptr_t tcg_getra_ext(uintptr_t ra)
+{
+ return is_tcg_gen_code(ra) ? GETRA_LDST(ra) : ra;
+}
#else
-# define GETPC_EXT() GETPC()
+# define GETRA_EXT() GETRA()
#endif
#if !defined(CONFIG_USER_ONLY)
diff --git a/include/exec/softmmu_template.h b/include/exec/softmmu_template.h
index eaca9e1035..2fc6ea3235 100644
--- a/include/exec/softmmu_template.h
+++ b/include/exec/softmmu_template.h
@@ -86,6 +86,9 @@ glue(glue(helper_ret_ld, SUFFIX), MMUSUFFIX)(CPUArchState *env,
target_ulong tlb_addr = env->tlb_table[mmu_idx][index].ADDR_READ;
uintptr_t haddr;
+ /* Adjust the given return address. */
+ retaddr -= GETPC_ADJ;
+
/* If the TLB entry is for a different page, reload and try again. */
if ((addr & TARGET_PAGE_MASK)
!= (tlb_addr & (TARGET_PAGE_MASK | TLB_INVALID_MASK))) {
@@ -121,10 +124,12 @@ glue(glue(helper_ret_ld, SUFFIX), MMUSUFFIX)(CPUArchState *env,
#endif
addr1 = addr & ~(DATA_SIZE - 1);
addr2 = addr1 + DATA_SIZE;
- res1 = glue(glue(helper_ret_ld, SUFFIX), MMUSUFFIX)(env, addr1,
- mmu_idx, retaddr);
- res2 = glue(glue(helper_ret_ld, SUFFIX), MMUSUFFIX)(env, addr2,
- mmu_idx, retaddr);
+ /* Note the adjustment at the beginning of the function.
+ Undo that for the recursion. */
+ res1 = glue(glue(helper_ret_ld, SUFFIX), MMUSUFFIX)
+ (env, addr1, mmu_idx, retaddr + GETPC_ADJ);
+ res2 = glue(glue(helper_ret_ld, SUFFIX), MMUSUFFIX)
+ (env, addr2, mmu_idx, retaddr + GETPC_ADJ);
shift = (addr & (DATA_SIZE - 1)) * 8;
#ifdef TARGET_WORDS_BIGENDIAN
res = (res1 << shift) | (res2 >> ((DATA_SIZE * 8) - shift));
@@ -150,7 +155,7 @@ glue(glue(helper_ld, SUFFIX), MMUSUFFIX)(CPUArchState *env, target_ulong addr,
int mmu_idx)
{
return glue(glue(helper_ret_ld, SUFFIX), MMUSUFFIX)(env, addr, mmu_idx,
- GETPC_EXT());
+ GETRA_EXT());
}
#ifndef SOFTMMU_CODE_ACCESS
@@ -182,6 +187,9 @@ glue(glue(helper_ret_st, SUFFIX), MMUSUFFIX)(CPUArchState *env,
target_ulong tlb_addr = env->tlb_table[mmu_idx][index].addr_write;
uintptr_t haddr;
+ /* Adjust the given return address. */
+ retaddr -= GETPC_ADJ;
+
/* If the TLB entry is for a different page, reload and try again. */
if ((addr & TARGET_PAGE_MASK)
!= (tlb_addr & (TARGET_PAGE_MASK | TLB_INVALID_MASK))) {
@@ -223,8 +231,10 @@ glue(glue(helper_ret_st, SUFFIX), MMUSUFFIX)(CPUArchState *env,
#else
uint8_t val8 = val >> (i * 8);
#endif
+ /* Note the adjustment at the beginning of the function.
+ Undo that for the recursion. */
glue(helper_ret_stb, MMUSUFFIX)(env, addr + i, val8,
- mmu_idx, retaddr);
+ mmu_idx, retaddr + GETPC_ADJ);
}
return;
}
@@ -245,7 +255,7 @@ glue(glue(helper_st, SUFFIX), MMUSUFFIX)(CPUArchState *env, target_ulong addr,
DATA_TYPE val, int mmu_idx)
{
glue(glue(helper_ret_st, SUFFIX), MMUSUFFIX)(env, addr, val, mmu_idx,
- GETPC_EXT());
+ GETRA_EXT());
}
#endif /* !defined(SOFTMMU_CODE_ACCESS) */