diff options
| -rw-r--r-- | linux-user/syscall.c | 37 |
1 files changed, 29 insertions, 8 deletions
diff --git a/linux-user/syscall.c b/linux-user/syscall.c index b975730..608924a 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -709,29 +709,44 @@ char *target_strerror(int err) static abi_ulong target_brk; static abi_ulong target_original_brk; +static abi_ulong brk_page; void target_set_brk(abi_ulong new_brk) { target_original_brk = target_brk = HOST_PAGE_ALIGN(new_brk); + brk_page = HOST_PAGE_ALIGN(target_brk); } +//#define DEBUGF_BRK(message, args...) do { fprintf(stderr, (message), ## args); } while (0) +#define DEBUGF_BRK(message, args...) + /* do_brk() must return target values and target errnos. */ abi_long do_brk(abi_ulong new_brk) { - abi_ulong brk_page; abi_long mapped_addr; int new_alloc_size; - if (!new_brk) + DEBUGF_BRK("do_brk(%#010x) -> ", new_brk); + + if (!new_brk) { + DEBUGF_BRK("%#010x (!new_brk)\n", target_brk); return target_brk; - if (new_brk < target_original_brk) + } + if (new_brk < target_original_brk) { + DEBUGF_BRK("%#010x (new_brk < target_original_brk)\n", target_brk); return target_brk; + } - brk_page = HOST_PAGE_ALIGN(target_brk); - - /* If the new brk is less than this, set it and we're done... */ - if (new_brk < brk_page) { + /* If the new brk is less than the highest page reserved to the + * target heap allocation, set it and we're almost done... */ + if (new_brk <= brk_page) { + /* Heap contents are initialized to zero, as for anonymous + * mapped pages. */ + if (new_brk > target_brk) { + memset(g2h(target_brk), 0, new_brk - target_brk); + } target_brk = new_brk; + DEBUGF_BRK("%#010x (new_brk <= brk_page)\n", target_brk); return target_brk; } @@ -741,13 +756,15 @@ abi_long do_brk(abi_ulong new_brk) * itself); instead we treat "mapped but at wrong address" as * a failure and unmap again. */ - new_alloc_size = HOST_PAGE_ALIGN(new_brk - brk_page + 1); + new_alloc_size = HOST_PAGE_ALIGN(new_brk - brk_page); mapped_addr = get_errno(target_mmap(brk_page, new_alloc_size, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, 0, 0)); if (mapped_addr == brk_page) { target_brk = new_brk; + brk_page = HOST_PAGE_ALIGN(target_brk); + DEBUGF_BRK("%#010x (mapped_addr == brk_page)\n", target_brk); return target_brk; } else if (mapped_addr != -1) { /* Mapped but at wrong address, meaning there wasn't actually @@ -755,6 +772,10 @@ abi_long do_brk(abi_ulong new_brk) */ target_munmap(mapped_addr, new_alloc_size); mapped_addr = -1; + DEBUGF_BRK("%#010x (mapped_addr != -1)\n", target_brk); + } + else { + DEBUGF_BRK("%#010x (otherwise)\n", target_brk); } #if defined(TARGET_ALPHA) |