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elf: add buffer at the top of stack

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Matheus
2023-08-07 20:01:53 -03:00
parent 739ce33c60
commit c42c1d2e24
1 changed files with 4 additions and 2 deletions
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kernel-src/sys/elf.c
+4 -2
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@@ -207,6 +207,7 @@ int elf_load(vnode_t *vnode, void *base, void **entry, char **interpreter, auxv6
#define STACK_MMUFLAGS (ARCH_MMU_FLAGS_READ | ARCH_MMU_FLAGS_WRITE | ARCH_MMU_FLAGS_NOEXEC | ARCH_MMU_FLAGS_USER)
#define STACK_SIZE (1024 * 1024 * 4)
#define STACK_TOP_BUFFER 8
void *elf_preparestack(void *top, auxv64list_t *auxv64, char **argv, char **envp) {
size_t argc;
@@ -223,8 +224,8 @@ void *elf_preparestack(void *top, auxv64list_t *auxv64, char **argv, char **envp
// make sure stack will be 16 byte aligned on entry
int alignment = ((argc + 1) + (envc + 1) + 1) & 1 ? 8 : 0;
// env data + arg data + pointers to arg and env data + argc
size_t initialsize = argdatasize + envdatasize + (argc + envc) * sizeof(char *) + sizeof(size_t) + sizeof(auxv64list_t) + alignment;
// env data + arg data + pointers to arg and env data + argc + buffer at the top
size_t initialsize = argdatasize + envdatasize + (argc + envc) * sizeof(char *) + sizeof(size_t) + sizeof(auxv64list_t) + alignment + STACK_TOP_BUFFER;
size_t initialsizeround = ROUND_UP(initialsize, PAGE_SIZE);
void *initialpagebase = (void *)((uintptr_t)top - initialsizeround);
@@ -236,6 +237,7 @@ void *elf_preparestack(void *top, auxv64list_t *auxv64, char **argv, char **envp
if (vmm_map(stackbase, unallocatedsize, VMM_FLAGS_EXACT, STACK_MMUFLAGS, NULL) == NULL)
return NULL;
top = (void *)((uintptr_t)top - STACK_TOP_BUFFER);
char *argdatastart = (char *)((uintptr_t)top - argdatasize);
char *envdatastart = (char *)((uintptr_t)argdatastart - envdatasize);