flat: fix data sections alignment

The flat loader uses an architecture's flat_stack_align() to align the
stack but assumes word-alignment is enough for the data sections.

However, on the Xtensa S6000 we have registers up to 128bit width
which can be used from userspace and therefor need userspace stack and
data-section alignment of at least this size.

This patch drops flat_stack_align() and uses the same alignment that
is required for slab caches, ARCH_SLAB_MINALIGN, or wordsize if it's
not defined by the architecture.

It also fixes m32r which was obviously kaput, aligning an
uninitialized stack entry instead of the stack pointer.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Oskar Schirmer <os@emlix.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Bryan Wu <cooloney@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Cc: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Johannes Weiner <jw@emlix.com>
Acked-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/arm/include/asm/flat.h b/arch/arm/include/asm/flat.h
index 1d77e51907f6ddb70f5aa8123583827bffaa676c..59426a4595c9cb90bcb765843f89295bd20f6797 100644 (file)
--- a/arch/arm/include/asm/flat.h
+++ b/arch/arm/include/asm/flat.h
@@ -5,9 +5,6 @@
 #ifndef __ARM_FLAT_H__
 #define __ARM_FLAT_H__
 
-/* An odd number of words will be pushed after this alignment, so
-   deliberately misalign the value.  */
-#define        flat_stack_align(sp)    sp = (void *)(((unsigned long)(sp) - 4) | 4)
 #define        flat_argvp_envp_on_stack()              1
 #define        flat_old_ram_flag(flags)                (flags)
 #define        flat_reloc_valid(reloc, size)           ((reloc) <= (size))

diff --git a/arch/blackfin/include/asm/flat.h b/arch/blackfin/include/asm/flat.h
index e70074e05f4ef095e33beb1cf28ede8ae817f980..733a178d782d0dd8e77e2c619f7b67d3271d2500 100644 (file)
--- a/arch/blackfin/include/asm/flat.h
+++ b/arch/blackfin/include/asm/flat.h
@@ -10,7 +10,6 @@
 
 #include <asm/unaligned.h>
 
-#define        flat_stack_align(sp)    /* nothing needed */
 #define        flat_argvp_envp_on_stack()              0
 #define        flat_old_ram_flag(flags)                (flags)
 

diff --git a/arch/h8300/include/asm/flat.h b/arch/h8300/include/asm/flat.h
index 2a873508a9a101b359483ebbf086f84aa769f0f0..bd12b31b90e60b3df56b0d8080e4bd86df98ce79 100644 (file)
--- a/arch/h8300/include/asm/flat.h
+++ b/arch/h8300/include/asm/flat.h
@@ -5,7 +5,6 @@
 #ifndef __H8300_FLAT_H__
 #define __H8300_FLAT_H__
 
-#define        flat_stack_align(sp)                    /* nothing needed */
 #define        flat_argvp_envp_on_stack()              1
 #define        flat_old_ram_flag(flags)                1
 #define        flat_reloc_valid(reloc, size)           ((reloc) <= (size))

diff --git a/arch/m32r/include/asm/flat.h b/arch/m32r/include/asm/flat.h
index d851cf0c4aa5ecff7902da7a54fdab618eccdad4..5d711c4688fb9f8162fd017a7e35451ad4c41da6 100644 (file)
--- a/arch/m32r/include/asm/flat.h
+++ b/arch/m32r/include/asm/flat.h
@@ -12,7 +12,6 @@
 #ifndef __ASM_M32R_FLAT_H
 #define __ASM_M32R_FLAT_H
 
-#define        flat_stack_align(sp)            (*sp += (*sp & 3 ? (4 - (*sp & 3)): 0))
 #define        flat_argvp_envp_on_stack()              0
 #define        flat_old_ram_flag(flags)                (flags)
 #define        flat_set_persistent(relval, p)          0

diff --git a/arch/m68k/include/asm/flat.h b/arch/m68k/include/asm/flat.h
index 814b5174a8e0ffb623aa96e65f9b2a1b52a4ddad..a0e290793978b35dd89586eba50c4e1f7950f1ca 100644 (file)
--- a/arch/m68k/include/asm/flat.h
+++ b/arch/m68k/include/asm/flat.h
@@ -5,7 +5,6 @@
 #ifndef __M68KNOMMU_FLAT_H__
 #define __M68KNOMMU_FLAT_H__
 
-#define        flat_stack_align(sp)                    /* nothing needed */
 #define        flat_argvp_envp_on_stack()              1
 #define        flat_old_ram_flag(flags)                (flags)
 #define        flat_reloc_valid(reloc, size)           ((reloc) <= (size))

diff --git a/arch/sh/include/asm/flat.h b/arch/sh/include/asm/flat.h
index d3b2b4f109e36ec68a61c7244ef7d4d48e9c335f..5d84df5e27f658972bf9b3acc3c9dd2267bf0176 100644 (file)
--- a/arch/sh/include/asm/flat.h
+++ b/arch/sh/include/asm/flat.h
@@ -12,7 +12,6 @@
 #ifndef __ASM_SH_FLAT_H
 #define __ASM_SH_FLAT_H
 
-#define        flat_stack_align(sp)                    /* nothing needed */
 #define        flat_argvp_envp_on_stack()              0
 #define        flat_old_ram_flag(flags)                (flags)
 #define        flat_reloc_valid(reloc, size)           ((reloc) <= (size))

diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index 5cebf0b37798422ff097260f657dc128ee2b0b58..697f6b5f13139ac5ea95a3f7456687299f26775e 100644 (file)
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -41,6 +41,7 @@
 #include <asm/uaccess.h>
 #include <asm/unaligned.h>
 #include <asm/cacheflush.h>
+#include <asm/page.h>
 
 /****************************************************************************/
 
@@ -54,6 +55,18 @@
 #define        DBG_FLT(a...)
 #endif
 
+/*
+ * User data (stack, data section and bss) needs to be aligned
+ * for the same reasons as SLAB memory is, and to the same amount.
+ * Avoid duplicating architecture specific code by using the same
+ * macro as with SLAB allocation:
+ */
+#ifdef ARCH_SLAB_MINALIGN
+#define FLAT_DATA_ALIGN        (ARCH_SLAB_MINALIGN)
+#else
+#define FLAT_DATA_ALIGN        (sizeof(void *))
+#endif
+
 #define RELOC_FAILED 0xff00ff01                /* Relocation incorrect somewhere */
 #define UNLOADED_LIB 0x7ff000ff                /* Placeholder for unused library */
 
@@ -114,20 +127,18 @@ static unsigned long create_flat_tables(
        int envc = bprm->envc;
        char uninitialized_var(dummy);
 
-       sp = (unsigned long *) ((-(unsigned long)sizeof(char *))&(unsigned long) p);
+       sp = (unsigned long *)p;
+       sp -= (envc + argc + 2) + 1 + (flat_argvp_envp_on_stack() ? 2 : 0);
+       sp = (unsigned long *) ((unsigned long)sp & -FLAT_DATA_ALIGN);
+       argv = sp + 1 + (flat_argvp_envp_on_stack() ? 2 : 0);
+       envp = argv + (argc + 1);
 
-       sp -= envc+1;
-       envp = sp;
-       sp -= argc+1;
-       argv = sp;
-
-       flat_stack_align(sp);
        if (flat_argvp_envp_on_stack()) {
-               --sp; put_user((unsigned long) envp, sp);
-               --sp; put_user((unsigned long) argv, sp);
+               put_user((unsigned long) envp, sp + 2);
+               put_user((unsigned long) argv, sp + 1);
        }
 
-       put_user(argc,--sp);
+       put_user(argc, sp);
        current->mm->arg_start = (unsigned long) p;
        while (argc-->0) {
                put_user((unsigned long) p, argv++);
@@ -558,7 +569,9 @@ static int load_flat_file(struct linux_binprm * bprm,
                        ret = realdatastart;
                        goto err;
                }
-               datapos = realdatastart + MAX_SHARED_LIBS * sizeof(unsigned long);
+               datapos = ALIGN(realdatastart +
+                               MAX_SHARED_LIBS * sizeof(unsigned long),
+                               FLAT_DATA_ALIGN);
 
                DBG_FLT("BINFMT_FLAT: Allocated data+bss+stack (%d bytes): %x\n",
                                (int)(data_len + bss_len + stack_len), (int)datapos);
@@ -604,9 +617,12 @@ static int load_flat_file(struct linux_binprm * bprm,
                }
 
                realdatastart = textpos + ntohl(hdr->data_start);
-               datapos = realdatastart + MAX_SHARED_LIBS * sizeof(unsigned long);
-               reloc = (unsigned long *) (textpos + ntohl(hdr->reloc_start) +
-                               MAX_SHARED_LIBS * sizeof(unsigned long));
+               datapos = ALIGN(realdatastart +
+                               MAX_SHARED_LIBS * sizeof(unsigned long),
+                               FLAT_DATA_ALIGN);
+
+               reloc = (unsigned long *)
+                       (datapos + (ntohl(hdr->reloc_start) - text_len));
                memp = textpos;
                memp_size = len;
 #ifdef CONFIG_BINFMT_ZFLAT
@@ -854,7 +870,7 @@ static int load_flat_binary(struct linux_binprm * bprm, struct pt_regs * regs)
        stack_len = TOP_OF_ARGS - bprm->p;             /* the strings */
        stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */
        stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */
-
+       stack_len += FLAT_DATA_ALIGN - 1;  /* reserve for upcoming alignment */
        
        res = load_flat_file(bprm, &libinfo, 0, &stack_len);
        if (res > (unsigned long)-4096)