From fdbb84d1332ae0827d60f1a2ca03c7d5678c6edd Mon Sep 17 00:00:00 2001 From: Yeongkyoon Lee Date: Wed, 31 Oct 2012 16:04:24 +0900 Subject: [PATCH] tcg: Add extended GETPC mechanism for MMU helpers with ldst optimization Add GETPC_EXT which is used by MMU helpers to selectively calculate the code address of accessing guest memory when called from a qemu_ld/st optimized code or a C function. Currently, it supports only i386 and x86-64 hosts. Signed-off-by: Yeongkyoon Lee Signed-off-by: Blue Swirl --- exec-all.h | 36 ++++++++++++++++++++++++++++++++++++ exec.c | 11 +++++++++++ softmmu_template.h | 16 ++++++++-------- 3 files changed, 55 insertions(+), 8 deletions(-) diff --git a/exec-all.h b/exec-all.h index 2ea0e4fc24..ad6d22b6c5 100644 --- a/exec-all.h +++ b/exec-all.h @@ -310,6 +310,42 @@ extern uintptr_t tci_tb_ptr; # define GETPC() ((uintptr_t)__builtin_return_address(0) - 1) #endif +#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__) +/* To avoid broken disassembling, long jmp is used for embedding fast path pc, + so that the destination is the next code of fast path, though this jmp is + never executed. + + call MMU helper + jmp POST_PROC (2byte) <- GETRA() + jmp NEXT_CODE (5byte) + POST_PROCESS ... <- GETRA() + 7 + */ +# define GETRA() ((uintptr_t)__builtin_return_address(0)) +# define GETPC_LDST() ((uintptr_t)(GETRA() + 7 + \ + *(int32_t *)((void *)GETRA() + 3) - 1)) +# else +# error "CONFIG_QEMU_LDST_OPTIMIZATION needs GETPC_LDST() implementation!" +# endif +bool is_tcg_gen_code(uintptr_t pc_ptr); +# define GETPC_EXT() (is_tcg_gen_code(GETRA()) ? GETPC_LDST() : GETPC()) +#else +# define GETPC_EXT() GETPC() +#endif + #if !defined(CONFIG_USER_ONLY) struct MemoryRegion *iotlb_to_region(hwaddr index); diff --git a/exec.c b/exec.c index df6793812f..8bff743a62 100644 --- a/exec.c +++ b/exec.c @@ -1390,6 +1390,17 @@ void tb_link_page(TranslationBlock *tb, mmap_unlock(); } +#if defined(CONFIG_QEMU_LDST_OPTIMIZATION) && defined(CONFIG_SOFTMMU) +/* check whether the given addr is in TCG generated code buffer or not */ +bool is_tcg_gen_code(uintptr_t tc_ptr) +{ + /* This can be called during code generation, code_gen_buffer_max_size + is used instead of code_gen_ptr for upper boundary checking */ + return (tc_ptr >= (uintptr_t)code_gen_buffer && + tc_ptr < (uintptr_t)(code_gen_buffer + code_gen_buffer_max_size)); +} +#endif + /* find the TB 'tb' such that tb[0].tc_ptr <= tc_ptr < tb[1].tc_ptr. Return NULL if not found */ TranslationBlock *tb_find_pc(uintptr_t tc_ptr) diff --git a/softmmu_template.h b/softmmu_template.h index 20d6baba68..ce30d8bddc 100644 --- a/softmmu_template.h +++ b/softmmu_template.h @@ -111,13 +111,13 @@ glue(glue(helper_ld, SUFFIX), MMUSUFFIX)(CPUArchState *env, target_ulong addr, /* IO access */ if ((addr & (DATA_SIZE - 1)) != 0) goto do_unaligned_access; - retaddr = GETPC(); + retaddr = GETPC_EXT(); ioaddr = env->iotlb[mmu_idx][index]; res = glue(io_read, SUFFIX)(env, ioaddr, addr, retaddr); } else if (((addr & ~TARGET_PAGE_MASK) + DATA_SIZE - 1) >= TARGET_PAGE_SIZE) { /* slow unaligned access (it spans two pages or IO) */ do_unaligned_access: - retaddr = GETPC(); + retaddr = GETPC_EXT(); #ifdef ALIGNED_ONLY do_unaligned_access(env, addr, READ_ACCESS_TYPE, mmu_idx, retaddr); #endif @@ -128,7 +128,7 @@ glue(glue(helper_ld, SUFFIX), MMUSUFFIX)(CPUArchState *env, target_ulong addr, uintptr_t addend; #ifdef ALIGNED_ONLY if ((addr & (DATA_SIZE - 1)) != 0) { - retaddr = GETPC(); + retaddr = GETPC_EXT(); do_unaligned_access(env, addr, READ_ACCESS_TYPE, mmu_idx, retaddr); } #endif @@ -138,7 +138,7 @@ glue(glue(helper_ld, SUFFIX), MMUSUFFIX)(CPUArchState *env, target_ulong addr, } } else { /* the page is not in the TLB : fill it */ - retaddr = GETPC(); + retaddr = GETPC_EXT(); #ifdef ALIGNED_ONLY if ((addr & (DATA_SIZE - 1)) != 0) do_unaligned_access(env, addr, READ_ACCESS_TYPE, mmu_idx, retaddr); @@ -257,12 +257,12 @@ void glue(glue(helper_st, SUFFIX), MMUSUFFIX)(CPUArchState *env, /* IO access */ if ((addr & (DATA_SIZE - 1)) != 0) goto do_unaligned_access; - retaddr = GETPC(); + retaddr = GETPC_EXT(); ioaddr = env->iotlb[mmu_idx][index]; glue(io_write, SUFFIX)(env, ioaddr, val, addr, retaddr); } else if (((addr & ~TARGET_PAGE_MASK) + DATA_SIZE - 1) >= TARGET_PAGE_SIZE) { do_unaligned_access: - retaddr = GETPC(); + retaddr = GETPC_EXT(); #ifdef ALIGNED_ONLY do_unaligned_access(env, addr, 1, mmu_idx, retaddr); #endif @@ -273,7 +273,7 @@ void glue(glue(helper_st, SUFFIX), MMUSUFFIX)(CPUArchState *env, uintptr_t addend; #ifdef ALIGNED_ONLY if ((addr & (DATA_SIZE - 1)) != 0) { - retaddr = GETPC(); + retaddr = GETPC_EXT(); do_unaligned_access(env, addr, 1, mmu_idx, retaddr); } #endif @@ -283,7 +283,7 @@ void glue(glue(helper_st, SUFFIX), MMUSUFFIX)(CPUArchState *env, } } else { /* the page is not in the TLB : fill it */ - retaddr = GETPC(); + retaddr = GETPC_EXT(); #ifdef ALIGNED_ONLY if ((addr & (DATA_SIZE - 1)) != 0) do_unaligned_access(env, addr, 1, mmu_idx, retaddr); -- 2.39.2