diff options
Diffstat (limited to 'recipes/qemu/qemu-0.12.5/qemu-sh4-improve-tlb.patch')
| -rw-r--r-- | recipes/qemu/qemu-0.12.5/qemu-sh4-improve-tlb.patch | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/recipes/qemu/qemu-0.12.5/qemu-sh4-improve-tlb.patch b/recipes/qemu/qemu-0.12.5/qemu-sh4-improve-tlb.patch new file mode 100644 index 0000000000..0742bb0941 --- /dev/null +++ b/recipes/qemu/qemu-0.12.5/qemu-sh4-improve-tlb.patch @@ -0,0 +1,120 @@ +From 829a49274f6741c0f3d3a2ba4698baf381a7e264 Mon Sep 17 00:00:00 2001 +From: Aurelien Jarno <aurelien@aurel32.net> +Date: Sun, 09 Jan 2011 22:53:45 +0000 +Subject: target-sh4: improve TLB + +SH4 is using 16-bit instructions which means most of the constants are +loaded through a constant pool at the end of the subroutine. The same +memory page is therefore accessed in exec and read mode. + +With the current implementation, a QEMU TLB entry is set to read or +read/write mode after an UTLB search and to exec mode after an ITLB +search, which causes a lot of TLB exceptions to switch from read or +read/write to exec and vice versa. + +This patch optimizes that by already setting the QEMU TLB entry in read +or read/write mode when an UTLB entry is copied into ITLB (during an +ITLB miss). This improve the emulation speed by about 14%. + +Signed-off-by: Aurelien Jarno <aurelien@aurel32.net> +--- +Index: qemu-0.12.5/target-sh4/helper.c +=================================================================== +--- qemu-0.12.5.orig/target-sh4/helper.c 2011-01-09 15:41:39.000000000 -0800 ++++ qemu-0.12.5/target-sh4/helper.c 2011-01-09 15:54:43.808656002 -0800 +@@ -295,36 +295,41 @@ + env->mmucr = (env->mmucr & 0xffff03ff) | (urc << 10); + } + +-/* Find itlb entry - update itlb from utlb if necessary and asked for ++/* Copy and utlb entry into itlb ++ Return entry ++*/ ++static int copy_utlb_entry_itlb(CPUState *env, int utlb) ++{ ++ int itlb; ++ ++ tlb_t * ientry; ++ itlb = itlb_replacement(env); ++ ientry = &env->itlb[itlb]; ++ if (ientry->v) { ++ tlb_flush_page(env, ientry->vpn << 10); ++ } ++ *ientry = env->utlb[utlb]; ++ update_itlb_use(env, itlb); ++ return itlb; ++} ++ ++/* Find itlb entry + Return entry, MMU_ITLB_MISS, MMU_ITLB_MULTIPLE or MMU_DTLB_MULTIPLE + Update the itlb from utlb if update is not 0 + */ + static int find_itlb_entry(CPUState * env, target_ulong address, +- int use_asid, int update) ++ int use_asid) + { +- int e, n; ++ int e; + + e = find_tlb_entry(env, address, env->itlb, ITLB_SIZE, use_asid); +- if (e == MMU_DTLB_MULTIPLE) ++ if (e == MMU_DTLB_MULTIPLE) { + e = MMU_ITLB_MULTIPLE; +- else if (e == MMU_DTLB_MISS && update) { +- e = find_tlb_entry(env, address, env->utlb, UTLB_SIZE, use_asid); +- if (e >= 0) { +- tlb_t * ientry; +- n = itlb_replacement(env); +- ientry = &env->itlb[n]; +- if (ientry->v) { +- if (!same_tlb_entry_exists(env->utlb, UTLB_SIZE, ientry)) +- tlb_flush_page(env, ientry->vpn << 10); +- } +- *ientry = env->utlb[e]; +- e = n; +- } else if (e == MMU_DTLB_MISS) +- e = MMU_ITLB_MISS; +- } else if (e == MMU_DTLB_MISS) ++ } else if (e == MMU_DTLB_MISS) { + e = MMU_ITLB_MISS; +- if (e >= 0) ++ } else if (e >= 0) { + update_itlb_use(env, e); ++ } + return e; + } + +@@ -356,13 +361,31 @@ + use_asid = (env->mmucr & MMUCR_SV) == 0 || (env->sr & SR_MD) == 0; + + if (rw == 2) { +- n = find_itlb_entry(env, address, use_asid, 1); ++ n = find_itlb_entry(env, address, use_asid); + if (n >= 0) { + matching = &env->itlb[n]; + if (!(env->sr & SR_MD) && !(matching->pr & 2)) + n = MMU_ITLB_VIOLATION; + else +- *prot = PAGE_READ; ++ *prot = PAGE_EXEC; ++ } else { ++ n = find_utlb_entry(env, address, use_asid); ++ if (n >= 0) { ++ n = copy_utlb_entry_itlb(env, n); ++ matching = &env->itlb[n]; ++ if (!(env->sr & SR_MD) && !(matching->pr & 2)) { ++ n = MMU_ITLB_VIOLATION; ++ } else { ++ *prot = PAGE_READ | PAGE_EXEC; ++ if ((matching->pr & 1) && matching->d) { ++ *prot |= PAGE_WRITE; ++ } ++ } ++ } else if (n == MMU_DTLB_MULTIPLE) { ++ n = MMU_ITLB_MULTIPLE; ++ } else if (n == MMU_DTLB_MISS) { ++ n = MMU_ITLB_MISS; ++ } + } + } else { + n = find_utlb_entry(env, address, use_asid); |