[PATCH] More support for upward growing stacks

 - remove elf_caddr_t. It's positively dangerous to #define this since
   elf_caddr_t foo, bar; creates variables of different types (foo is
   char *, bar is char).
 - rewrite large chunks of create_elf_tables(), it needed cleaning anyway.
 - add upwards-growing stack support to create_elf_tables.
 - redefine the ARCH_DLINFO stuff on powerpc -- it's tested, works.
 - add upwards-growing-stack support to exec.c too.

arch/mips/kernel/irixelf.c

@@ -54,7 +54,6 @@ static struct linux_binfmt irix_format = {
 
 #ifndef elf_addr_t
 #define elf_addr_t unsigned long
-#define elf_caddr_t char *
 #endif
 
 #ifdef DEBUG_ELF
@@ -155,8 +154,8 @@ unsigned long * create_irix_tables(char * p, int argc, int envc,
 				   unsigned int interp_load_addr,
 				   struct pt_regs *regs, struct elf_phdr *ephdr)
 {
-	elf_caddr_t *argv;
-	elf_caddr_t *envp;
+	elf_addr_t *argv;
+	elf_addr_t *envp;
 	elf_addr_t *sp, *csp;
 	
 #ifdef DEBUG_ELF
@@ -202,20 +201,20 @@ unsigned long * create_irix_tables(char * p, int argc, int envc,
 #undef NEW_AUX_ENT
 
 	sp -= envc+1;
-	envp = (elf_caddr_t *) sp;
+	envp = sp;
 	sp -= argc+1;
-	argv = (elf_caddr_t *) sp;
+	argv = sp;
 
 	__put_user((elf_addr_t)argc,--sp);
 	current->mm->arg_start = (unsigned long) p;
 	while (argc-->0) {
-		__put_user((elf_caddr_t)(unsigned long)p,argv++);
+		__put_user((unsigned long)p,argv++);
 		p += strlen_user(p);
 	}
 	__put_user(NULL, argv);
 	current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 	while (envc-->0) {
-		__put_user((elf_caddr_t)(unsigned long)p,envp++);
+		__put_user((unsigned long)p,envp++);
 		p += strlen_user(p);
 	}
 	__put_user(NULL, envp);

arch/mips64/kernel/binfmt_elf32.c

@@ -80,7 +80,6 @@ struct elf_prpsinfo32
 };
 
 #define elf_addr_t	u32
-#define elf_caddr_t	u32
 #define init_elf_binfmt init_elf32_binfmt
 #undef CONFIG_BINFMT_ELF
 #ifdef CONFIG_BINFMT_ELF32

arch/s390x/kernel/binfmt_elf32.c

@@ -166,7 +166,6 @@ struct elf_prpsinfo32
 #define NEW_TO_OLD_GID(gid) ((gid) > 65535) ? (u16)overflowgid : (u16)(gid) 
 
 #define elf_addr_t	u32
-#define elf_caddr_t	u32
 /*
 #define init_elf_binfmt init_elf32_binfmt
 */

arch/sparc64/kernel/binfmt_elf32.c

@@ -147,7 +147,6 @@ jiffies_to_timeval32(unsigned long jiffies, struct timeval32 *value)
 }
 
 #define elf_addr_t	u32
-#define elf_caddr_t	u32
 #undef start_thread
 #define start_thread start_thread32
 #define init_elf_binfmt init_elf32_binfmt

arch/x86_64/ia32/ia32_binfmt.c

@@ -186,7 +186,6 @@ MODULE_AUTHOR("Eric Youngdale, Andi Kleen");
 #undef MODULE_AUTHOR
 
 #define elf_addr_t __u32
-#define elf_caddr_t __u32
 
 static void elf32_init(struct pt_regs *);
 

fs/exec.c

@@ -323,9 +323,50 @@ int setup_arg_pages(struct linux_binprm *bprm)
 {
 	unsigned long stack_base;
 	struct vm_area_struct *mpnt;
+	struct mm_struct *mm = current->mm;
 	int i;
 
-	stack_base = STACK_TOP - MAX_ARG_PAGES*PAGE_SIZE;
+#ifdef ARCH_STACK_GROWSUP
+	/* Move the argument and environment strings to the bottom of the
+	 * stack space.
+	 */
+	int offset, j;
+	char *to, *from;
+
+	/* Start by shifting all the pages down */
+	i = 0;
+	for (j = 0; j < MAX_ARG_PAGES; j++) {
+		struct page *page = bprm->page[j];
+		if (!page)
+			continue;
+		bprm->page[i++] = page;
+	}
+
+	/* Now move them within their pages */
+	offset = bprm->p % PAGE_SIZE;
+	to = kmap(bprm->page[0]);
+	for (j = 1; j < i; j++) {
+		memmove(to, to + offset, PAGE_SIZE - offset);
+		from = kmap(bprm->page[j]);
+		memcpy(to + PAGE_SIZE - offset, from, offset);
+		kunmap(bprm[j - 1]);
+		to = from;
+	}
+	memmove(to, to + offset, PAGE_SIZE - offset);
+	kunmap(bprm[j - 1]);
+
+	/* Adjust bprm->p to point to the end of the strings. */
+	bprm->p = PAGE_SIZE * i - offset;
+	stack_base = STACK_TOP - current->rlim[RLIMIT_STACK].rlim_max;
+	mm->arg_start = stack_base;
+
+	/* zero pages that were copied above */
+	while (i < MAX_ARG_PAGES)
+		bprm->page[i++] = NULL;
+#else
+	stack_base = STACK_TOP - MAX_ARG_PAGES * PAGE_SIZE;
+	mm->arg_start = bprm->p + stack_base;
+#endif
 
 	bprm->p += stack_base;
 	if (bprm->loader)
@@ -333,7 +374,7 @@ int setup_arg_pages(struct linux_binprm *bprm)
 	bprm->exec += stack_base;
 
 	mpnt = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
-	if (!mpnt) 
+	if (!mpnt)
 		return -ENOMEM;
 
 	if (!vm_enough_memory((STACK_TOP - (PAGE_MASK & (unsigned long) bprm->p))>>PAGE_SHIFT)) {
@@ -341,19 +382,25 @@ int setup_arg_pages(struct linux_binprm *bprm)
 		return -ENOMEM;
 	}
 
-	down_write(&current->mm->mmap_sem);
+	down_write(&mm->mmap_sem);
 	{
-		mpnt->vm_mm = current->mm;
+		mpnt->vm_mm = mm;
+#ifdef ARCH_STACK_GROWSUP
+		mpnt->vm_start = stack_base;
+		mpnt->vm_end = PAGE_MASK &
+			(PAGE_SIZE - 1 + (unsigned long) bprm->p);
+#else
 		mpnt->vm_start = PAGE_MASK & (unsigned long) bprm->p;
 		mpnt->vm_end = STACK_TOP;
+#endif
 		mpnt->vm_page_prot = PAGE_COPY;
 		mpnt->vm_flags = VM_STACK_FLAGS;
 		mpnt->vm_ops = NULL;
 		mpnt->vm_pgoff = 0;
 		mpnt->vm_file = NULL;
 		mpnt->vm_private_data = (void *) 0;
-		insert_vm_struct(current->mm, mpnt);
-		current->mm->total_vm = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT;
+		insert_vm_struct(mm, mpnt);
+		mm->total_vm = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT;
 	} 
 
 	for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
@@ -364,7 +411,7 @@ int setup_arg_pages(struct linux_binprm *bprm)
 		}
 		stack_base += PAGE_SIZE;
 	}
-	up_write(&current->mm->mmap_sem);
+	up_write(&mm->mmap_sem);
 	
 	return 0;
 }
@@ -732,7 +779,6 @@ void compute_creds(struct linux_binprm *bprm)
 	security_ops->bprm_compute_creds(bprm);
 }
 
-
 void remove_arg_zero(struct linux_binprm *bprm)
 {
 	if (bprm->argc) {
@@ -854,7 +900,6 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
 	return retval;
 }
 
-
 /*
  * sys_execve() executes a new program.
  */

include/asm-ia64/ia32.h

@@ -334,7 +334,6 @@ void ia64_elf32_init(struct pt_regs *regs);
 #define ELF_PLAT_INIT(_r)	ia64_elf32_init(_r)
 
 #define elf_addr_t	u32
-#define elf_caddr_t	u32
 
 /* ELF register definitions.  This is needed for core dump support.  */
 

include/asm-mips64/elf.h

@@ -31,7 +31,7 @@ typedef elf_fpreg_t elf_fpregset_t[ELF_NFPREG];
 									\
 	if (__h->e_machine != EM_MIPS)					\
 		__res = 0;						\
-	if (sizeof(elf_caddr_t) == 8 &&					\
+	if (sizeof(elf_addr_t) == 8 &&					\
 	    __h->e_ident[EI_CLASS] == ELFCLASS32)			\
 	        __res = 0;						\
 									\

include/asm-ppc/elf.h

@@ -98,19 +98,14 @@ extern int ucache_bsize;
  * - for compatibility with glibc ARCH_DLINFO must always be defined on PPC,
  *   even if DLINFO_ARCH_ITEMS goes to zero or is undefined.
  */
-#define DLINFO_ARCH_ITEMS	3
 #define ARCH_DLINFO							\
 do {									\
-	sp -= DLINFO_ARCH_ITEMS * 2;					\
-	NEW_AUX_ENT(0, AT_DCACHEBSIZE, dcache_bsize);			\
-	NEW_AUX_ENT(1, AT_ICACHEBSIZE, icache_bsize);			\
-	NEW_AUX_ENT(2, AT_UCACHEBSIZE, ucache_bsize);			\
-	/*								\
-	 * Now handle glibc compatibility.				\
-	 */								\
-	sp -= 2*2;							\
-	NEW_AUX_ENT(0, AT_IGNOREPPC, AT_IGNOREPPC);			\
-	NEW_AUX_ENT(1, AT_IGNOREPPC, AT_IGNOREPPC);			\
+	NEW_AUX_ENT(AT_DCACHEBSIZE, dcache_bsize);			\
+	NEW_AUX_ENT(AT_ICACHEBSIZE, icache_bsize);			\
+	NEW_AUX_ENT(AT_UCACHEBSIZE, ucache_bsize);			\
+	/* Now handle glibc compatibility. */				\
+	NEW_AUX_ENT(AT_IGNOREPPC, AT_IGNOREPPC);			\
+	NEW_AUX_ENT(AT_IGNOREPPC, AT_IGNOREPPC);			\
  } while (0)
 
 #endif /* __KERNEL__ */

include/asm-ppc64/elf.h

@@ -31,13 +31,11 @@ typedef elf_greg_t32 elf_gregset_t32[ELF_NGREG];
   typedef elf_greg_t64 elf_greg_t;
   typedef elf_gregset_t64 elf_gregset_t;
 # define elf_addr_t unsigned long
-# define elf_caddr_t char *
 #else
   /* Assumption: ELF_ARCH == EM_PPC and ELF_CLASS == ELFCLASS32 */
   typedef elf_greg_t32 elf_greg_t;
   typedef elf_gregset_t32 elf_gregset_t;
 # define elf_addr_t u32
-# define elf_caddr_t u32
 #endif
 
 typedef double elf_fpreg_t;
@@ -122,19 +120,14 @@ extern int ucache_bsize;
  * - for compatibility with glibc ARCH_DLINFO must always be defined on PPC,
  *   even if DLINFO_ARCH_ITEMS goes to zero or is undefined.
  */
-#define DLINFO_ARCH_ITEMS	3
 #define ARCH_DLINFO							\
 do {									\
-	sp -= DLINFO_ARCH_ITEMS * 2;					\
-	NEW_AUX_ENT(0, AT_DCACHEBSIZE, dcache_bsize);			\
-	NEW_AUX_ENT(1, AT_ICACHEBSIZE, icache_bsize);			\
-	NEW_AUX_ENT(2, AT_UCACHEBSIZE, ucache_bsize);			\
-	/*								\
-	 * Now handle glibc compatibility.				\
-	 */								\
-	sp -= 2*2;							\
-	NEW_AUX_ENT(0, AT_IGNOREPPC, AT_IGNOREPPC);			\
-	NEW_AUX_ENT(1, AT_IGNOREPPC, AT_IGNOREPPC);			\
+	NEW_AUX_ENT(AT_DCACHEBSIZE, dcache_bsize);			\
+	NEW_AUX_ENT(AT_ICACHEBSIZE, icache_bsize);			\
+	NEW_AUX_ENT(AT_UCACHEBSIZE, ucache_bsize);			\
+	/* Now handle glibc compatibility. */				\
+	NEW_AUX_ENT(AT_IGNOREPPC, AT_IGNOREPPC);			\
+	NEW_AUX_ENT(AT_IGNOREPPC, AT_IGNOREPPC);			\
  } while (0)
 
 #endif /* __PPC64_ELF_H */