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authorPaul Mundt <lethal@linux-sh.org>2008-05-19 00:34:45 -0400
committerPaul Mundt <lethal@linux-sh.org>2008-07-28 05:10:28 -0400
commit9b14ec35f03d89c88cba225add8b6eca15203964 (patch)
tree9502e80206d3e1ead9a0c553f9f719b99c0ceebd /fs
parente3b08600902e119b34ca03c4aaf99bde4b173dde (diff)
binfmt_elf_fdpic: Magical stack pointer index, for NEW_AUX_ENT compat.
While implementing binfmt_elf_fdpic on SH it quickly became apparent that SH was the first platform to support both binfmt_elf_fdpic and binfmt_elf, as well as the only of the FDPIC platforms to make use of the auxvt. Currently binfmt_elf_fdpic uses a special version of NEW_AUX_ENT() where the first argument is the entry displacement after csp has been adjusted, being reset after each adjustment. As we have no ability to sort this out through the platform's ARCH_DLINFO, this index needs to be managed entirely in create_elf_fdpic_tables(). Presently none of the platforms that set their own auxvt entries are able to do so through their respective ARCH_DLINFOs when using binfmt_elf_fdpic. In addition to this, binfmt_elf_fdpic has been looking at DLINFO_ARCH_ITEMS for the number of architecture-specific entries in the auxvt. This is legacy cruft, and is not defined by any platforms in-tree, even those that make heavy use of the auxvt. AT_VECTOR_SIZE_ARCH is always available, and contains the number that is of interest here, so we switch to using that unconditionally as well. As this has direct bearing on how much stack is used, platforms that have configurable (or dynamically adjustable) NEW_AUX_ENT calls need to either make AT_VECTOR_SIZE_ARCH more fine-grained, or leave it as a worst-case and live with some lost stack space if those entries aren't pushed (some platforms may also need to purposely sacrifice some space here for alignment considerations, as noted in the code -- although not an issue for any FDPIC-capable platform today). Signed-off-by: Paul Mundt <lethal@linux-sh.org> Acked-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/binfmt_elf_fdpic.c45
1 files changed, 25 insertions, 20 deletions
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index fdeadab2f18b..80c1f952ef78 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -470,6 +470,7 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
470 char __user *u_platform, *p; 470 char __user *u_platform, *p;
471 long hwcap; 471 long hwcap;
472 int loop; 472 int loop;
473 int nr; /* reset for each csp adjustment */
473 474
474 /* we're going to shovel a whole load of stuff onto the stack */ 475 /* we're going to shovel a whole load of stuff onto the stack */
475#ifdef CONFIG_MMU 476#ifdef CONFIG_MMU
@@ -542,10 +543,7 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
542 /* force 16 byte _final_ alignment here for generality */ 543 /* force 16 byte _final_ alignment here for generality */
543#define DLINFO_ITEMS 13 544#define DLINFO_ITEMS 13
544 545
545 nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0); 546 nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0) + AT_VECTOR_SIZE_ARCH;
546#ifdef DLINFO_ARCH_ITEMS
547 nitems += DLINFO_ARCH_ITEMS;
548#endif
549 547
550 csp = sp; 548 csp = sp;
551 sp -= nitems * 2 * sizeof(unsigned long); 549 sp -= nitems * 2 * sizeof(unsigned long);
@@ -557,39 +555,46 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
557 sp -= sp & 15UL; 555 sp -= sp & 15UL;
558 556
559 /* put the ELF interpreter info on the stack */ 557 /* put the ELF interpreter info on the stack */
560#define NEW_AUX_ENT(nr, id, val) \ 558#define NEW_AUX_ENT(id, val) \
561 do { \ 559 do { \
562 struct { unsigned long _id, _val; } __user *ent; \ 560 struct { unsigned long _id, _val; } __user *ent; \
563 \ 561 \
564 ent = (void __user *) csp; \ 562 ent = (void __user *) csp; \
565 __put_user((id), &ent[nr]._id); \ 563 __put_user((id), &ent[nr]._id); \
566 __put_user((val), &ent[nr]._val); \ 564 __put_user((val), &ent[nr]._val); \
565 nr++; \
567 } while (0) 566 } while (0)
568 567
568 nr = 0;
569 csp -= 2 * sizeof(unsigned long); 569 csp -= 2 * sizeof(unsigned long);
570 NEW_AUX_ENT(0, AT_NULL, 0); 570 NEW_AUX_ENT(AT_NULL, 0);
571 if (k_platform) { 571 if (k_platform) {
572 nr = 0;
572 csp -= 2 * sizeof(unsigned long); 573 csp -= 2 * sizeof(unsigned long);
573 NEW_AUX_ENT(0, AT_PLATFORM, 574 NEW_AUX_ENT(AT_PLATFORM,
574 (elf_addr_t) (unsigned long) u_platform); 575 (elf_addr_t) (unsigned long) u_platform);
575 } 576 }
576 577
578 nr = 0;
577 csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long); 579 csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
578 NEW_AUX_ENT( 0, AT_HWCAP, hwcap); 580 NEW_AUX_ENT(AT_HWCAP, hwcap);
579 NEW_AUX_ENT( 1, AT_PAGESZ, PAGE_SIZE); 581 NEW_AUX_ENT(AT_PAGESZ, PAGE_SIZE);
580 NEW_AUX_ENT( 2, AT_CLKTCK, CLOCKS_PER_SEC); 582 NEW_AUX_ENT(AT_CLKTCK, CLOCKS_PER_SEC);
581 NEW_AUX_ENT( 3, AT_PHDR, exec_params->ph_addr); 583 NEW_AUX_ENT(AT_PHDR, exec_params->ph_addr);
582 NEW_AUX_ENT( 4, AT_PHENT, sizeof(struct elf_phdr)); 584 NEW_AUX_ENT(AT_PHENT, sizeof(struct elf_phdr));
583 NEW_AUX_ENT( 5, AT_PHNUM, exec_params->hdr.e_phnum); 585 NEW_AUX_ENT(AT_PHNUM, exec_params->hdr.e_phnum);
584 NEW_AUX_ENT( 6, AT_BASE, interp_params->elfhdr_addr); 586 NEW_AUX_ENT(AT_BASE, interp_params->elfhdr_addr);
585 NEW_AUX_ENT( 7, AT_FLAGS, 0); 587 NEW_AUX_ENT(AT_FLAGS, 0);
586 NEW_AUX_ENT( 8, AT_ENTRY, exec_params->entry_addr); 588 NEW_AUX_ENT(AT_ENTRY, exec_params->entry_addr);
587 NEW_AUX_ENT( 9, AT_UID, (elf_addr_t) current->uid); 589 NEW_AUX_ENT(AT_UID, (elf_addr_t) current->uid);
588 NEW_AUX_ENT(10, AT_EUID, (elf_addr_t) current->euid); 590 NEW_AUX_ENT(AT_EUID, (elf_addr_t) current->euid);
589 NEW_AUX_ENT(11, AT_GID, (elf_addr_t) current->gid); 591 NEW_AUX_ENT(AT_GID, (elf_addr_t) current->gid);
590 NEW_AUX_ENT(12, AT_EGID, (elf_addr_t) current->egid); 592 NEW_AUX_ENT(AT_EGID, (elf_addr_t) current->egid);
591 593
592#ifdef ARCH_DLINFO 594#ifdef ARCH_DLINFO
595 nr = 0;
596 csp -= AT_VECTOR_SIZE_ARCH * 2 * sizeof(unsigned long);
597
593 /* ARCH_DLINFO must come last so platform specific code can enforce 598 /* ARCH_DLINFO must come last so platform specific code can enforce
594 * special alignment requirements on the AUXV if necessary (eg. PPC). 599 * special alignment requirements on the AUXV if necessary (eg. PPC).
595 */ 600 */