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https://github.com/Zenithsiz/ftmemsim-valgrind.git
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Initial data (brk) segment is setup on demand, when a first brk() syscall
is made. It cannot be established during client image initialization because that would conflict with a temporary stack which ld.so.1 (when executed directly) uses for loading the target dynamic executable. See PRE(sys_brk) in syswrap-solaris.c. Preparatory work for ldsoexec support. n-i-bz git-svn-id: svn://svn.valgrind.org/valgrind/trunk@15572
This commit is contained in:
Ivo Raisr
parent
8372cfdb0f
commit
542fa886dc
@ -747,63 +747,6 @@ static Addr setup_client_stack(void *init_sp,
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return client_SP;
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}
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/* Allocate the client data segment. It is an expandable anonymous mapping
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abutting a 1-page reservation. The data segment starts at VG_(brk_base)
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and runs up to VG_(brk_limit). None of these two values have to be
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page-aligned.
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Reservation segment is used to protect the data segment merging with
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a pre-existing segment. This should be no problem because address space
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manager ensures that requests for client address space are satisfied from
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the highest available addresses. However when memory is low, data segment
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can meet with mmap'ed objects and the reservation segment separates these.
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The page that contains VG_(brk_base) is already allocated by the program's
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loaded data segment. The brk syscall wrapper handles this special case.
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See the brk syscall wrapper for more information. */
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static void setup_client_dataseg(SizeT initial_size)
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{
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Bool ok;
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SysRes sres;
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Addr anon_start = VG_PGROUNDUP(VG_(brk_base));
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SizeT anon_size = VG_PGROUNDUP(initial_size);
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Addr resvn_start = anon_start + anon_size;
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SizeT resvn_size = VKI_PAGE_SIZE;
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const NSegment *seg;
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UInt prot;
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vg_assert(VG_IS_PAGE_ALIGNED(anon_size));
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vg_assert(VG_IS_PAGE_ALIGNED(resvn_size));
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vg_assert(VG_IS_PAGE_ALIGNED(anon_start));
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vg_assert(VG_IS_PAGE_ALIGNED(resvn_start));
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/* Stay sane (because there's been no brk activity yet). */
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vg_assert(VG_(brk_base) == VG_(brk_limit));
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/* Find the loaded data segment and remember its protection. */
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seg = VG_(am_find_nsegment)(VG_(brk_base) - 1);
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vg_assert(seg);
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prot = (seg->hasR ? VKI_PROT_READ : 0)
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| (seg->hasW ? VKI_PROT_WRITE : 0)
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| (seg->hasX ? VKI_PROT_EXEC : 0);
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/* Try to create the data segment and associated reservation where
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VG_(brk_base) says. */
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ok = VG_(am_create_reservation)(resvn_start, resvn_size, SmLower, anon_size);
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if (!ok) {
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/* That didn't work, we're hosed. */
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VG_(printf)("valgrind: cannot initialize a brk segment\n");
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VG_(exit)(1);
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/*NOTREACHED*/
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}
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vg_assert(ok);
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/* Map the data segment. */
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sres = VG_(am_mmap_anon_fixed_client)(anon_start, anon_size, prot);
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vg_assert(!sr_isError(sres));
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vg_assert(sr_Res(sres) == anon_start);
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}
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/*====================================================================*/
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/*=== TOP-LEVEL: VG_(setup_client_initial_image) ===*/
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/*====================================================================*/
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@ -898,26 +841,10 @@ IIFinaliseImageInfo VG_(ii_create_image)(IICreateImageInfo iicii,
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iifii.clstack_max_size);
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}
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//--------------------------------------------------------------
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// Setup client data (brk) segment. Initially segment at least
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// 1 MB and at most 8 MB large which abuts a 1-page reservation.
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// p: load_client() [for 'info' and hence VG_(brk_base)]
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//--------------------------------------------------------------
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{
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SizeT m1 = 1024 * 1024;
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SizeT m8 = 8 * m1;
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SizeT dseg_max_size = VG_(client_rlimit_data).rlim_cur;
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VG_(debugLog)(1, "initimg", "Setup client data (brk) segment at %#lx\n",
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VG_(brk_base));
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if (dseg_max_size < m1)
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dseg_max_size = m1;
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if (dseg_max_size > m8)
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dseg_max_size = m8;
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dseg_max_size = VG_PGROUNDUP(dseg_max_size);
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setup_client_dataseg(dseg_max_size);
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}
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/* Initial data (brk) segment is setup on demand, when a first brk() syscall
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is made. It cannot be established now because it would conflict with
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a temporary stack which ld.so.1 (when executed directly) uses for loading
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the target dynamic executable. See PRE(sys_brk) in syswrap-solaris.c. */
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return iifii;
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}
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@ -934,7 +861,6 @@ IIFinaliseImageInfo VG_(ii_create_image)(IICreateImageInfo iicii,
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void VG_(ii_finalise_image)(IIFinaliseImageInfo iifii)
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{
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ThreadArchState *arch = &VG_(threads)[1].arch;
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const NSegment *seg;
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# if defined(VGA_x86)
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vg_assert(0 == sizeof(VexGuestX86State) % LibVEX_GUEST_STATE_ALIGN);
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@ -990,14 +916,16 @@ void VG_(ii_finalise_image)(IIFinaliseImageInfo iifii)
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VG_TRACK(post_reg_write, Vg_CoreStartup, 1/*tid*/, 0/*offset*/,
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sizeof(VexGuestArchState));
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/* Tell the tool about the client data segment and then kill it which will
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make it inaccessible/unaddressable. */
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seg = VG_(am_find_nsegment)(VG_PGROUNDUP(VG_(brk_base)));
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vg_assert(seg);
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vg_assert(seg->kind == SkAnonC);
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VG_TRACK(new_mem_brk, VG_(brk_base), seg->end + 1 - VG_(brk_base),
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1/*tid*/);
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VG_TRACK(die_mem_brk, VG_(brk_base), seg->end + 1 - VG_(brk_base));
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/* Make inaccessible/unaddressable the end of the client data segment.
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See PRE(sys_brk) in syswrap-solaris.c for details. Nothing to do in
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case VG_(brk_base) starts on the beginning of a free page. */
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const NSegment *seg = VG_(am_find_nsegment)(VG_(brk_base));
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if (seg != NULL) {
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vg_assert((seg->kind == SkFileC) || (seg->kind == SkAnonC));
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VG_TRACK(new_mem_brk, VG_(brk_base), seg->end + 1 - VG_(brk_base),
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1 /* tid */);
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VG_TRACK(die_mem_brk, VG_(brk_base), seg->end + 1 - VG_(brk_base));
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}
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}
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#endif // defined(VGO_solaris)
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@ -1803,15 +1803,18 @@ PRE(sys_time)
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PRE_REG_READ0(long, "time");
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}
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/* Data segment for brk (heap).
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Initial data segment is established during image initialization
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(initimg-solaris.c). Notable facts:
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/* Data segment for brk (heap). It is an expandable anonymous mapping
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abutting a 1-page reservation. The data segment starts at VG_(brk_base)
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and runs up to VG_(brk_limit). None of these two values have to be
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page-aligned. Initial data segment is established on demand here (see
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initimg-solaris.c for rationale).
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Notable facts:
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- VG_(brk_base) is not page aligned; does not move
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- VG_(brk_limit) moves between [VG_(brk_base), data segment end]
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- data segment end is always page aligned
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- right after data segment end is 1-page reservation
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| heap |
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| heap | 1 page
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+------+------+--------------+-------+
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| BSS | anon | anon | resvn |
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+------+------+--------------+-------+
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@ -1824,9 +1827,63 @@ PRE(sys_time)
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VG_(brk_base) -- not page aligned -- does not move
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Because VG_(brk_base) is not page-aligned and is initially located within
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pre-established data segment, special care has to be taken in the code below
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to handle this feature.
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*/
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pre-established BSS (data) segment, special care has to be taken in the code
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below to handle this feature.
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Reservation segment is used to protect the data segment merging with
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a pre-existing segment. This should be no problem because address space
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manager ensures that requests for client address space are satisfied from
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the highest available addresses. However when memory is low, data segment
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can meet with mmap'ed objects and the reservation segment separates these.
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The page that contains VG_(brk_base) is already allocated by the program's
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loaded data segment. The brk syscall wrapper handles this special case. */
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/* Establishes initial data segment for brk (heap). */
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static Bool setup_client_dataseg(SizeT initial_size, ThreadId tid)
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{
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Addr anon_start = VG_PGROUNDUP(VG_(brk_base));
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SizeT anon_size = VG_PGROUNDUP(initial_size);
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Addr resvn_start = anon_start + anon_size;
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SizeT resvn_size = VKI_PAGE_SIZE;
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vg_assert(VG_IS_PAGE_ALIGNED(anon_size));
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vg_assert(VG_IS_PAGE_ALIGNED(resvn_size));
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vg_assert(VG_IS_PAGE_ALIGNED(anon_start));
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vg_assert(VG_IS_PAGE_ALIGNED(resvn_start));
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vg_assert(VG_(brk_base) == VG_(brk_limit));
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/* Find the loaded data segment and remember its protection. */
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const NSegment *seg = VG_(am_find_nsegment)(VG_(brk_base) - 1);
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vg_assert(seg != NULL);
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UInt prot = (seg->hasR ? VKI_PROT_READ : 0)
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| (seg->hasW ? VKI_PROT_WRITE : 0)
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| (seg->hasX ? VKI_PROT_EXEC : 0);
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/* Try to create the data segment and associated reservation where
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VG_(brk_base) says. */
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Bool ok = VG_(am_create_reservation)(resvn_start, resvn_size, SmLower,
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anon_size);
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if (!ok) {
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/* That didn't work, we're hosed. */
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return False;
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}
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/* Map the data segment. */
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SysRes sres = VG_(am_mmap_anon_fixed_client)(anon_start, anon_size, prot);
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vg_assert(!sr_isError(sres));
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vg_assert(sr_Res(sres) == anon_start);
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/* Tell the tool about the client data segment and then kill it which will
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make it initially inaccessible/unaddressable. */
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seg = VG_(am_find_nsegment)(anon_start);
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vg_assert(seg != NULL);
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vg_assert(seg->kind == SkAnonC);
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VG_TRACK(new_mem_brk, VG_(brk_base), seg->end + 1 - VG_(brk_base), tid);
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VG_TRACK(die_mem_brk, VG_(brk_base), seg->end + 1 - VG_(brk_base));
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return True;
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}
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static Bool brk_segment_established = False;
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PRE(sys_brk)
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{
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@ -1845,7 +1902,7 @@ PRE(sys_brk)
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PRINT("sys_brk ( %#lx )", ARG1);
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PRE_REG_READ1(unsigned long, "brk", vki_caddr_t, end_data_segment);
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if (!new_brk) {
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if (new_brk == 0) {
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/* brk(0) - specific to Solaris 11 only. */
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SET_STATUS_Success(old_brk_limit);
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return;
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@ -1866,6 +1923,33 @@ PRE(sys_brk)
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return;
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}
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if (!brk_segment_established) {
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/* Stay sane (because there should have been no brk activity yet). */
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vg_assert(VG_(brk_base) == VG_(brk_limit));
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/* Establish an initial data segment for brk (heap).
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Initially at least 1 MB and at most 8 MB large. */
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SizeT m1 = 1024 * 1024;
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SizeT m8 = 8 * m1;
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SizeT dseg_max_size = VG_(client_rlimit_data).rlim_cur;
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VG_(debugLog)(1, "syswrap-solaris", "Setup client data (brk) segment "
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"at %#lx\n", VG_(brk_base));
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if (dseg_max_size < m1)
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dseg_max_size = m1;
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if (dseg_max_size > m8)
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dseg_max_size = m8;
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dseg_max_size = VG_PGROUNDUP(dseg_max_size);
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if (!setup_client_dataseg(dseg_max_size, tid)) {
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VG_(umsg)("Cannot map memory to initialize brk segment in thread #%d "
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"at %#lx\n", tid, VG_(brk_base));
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SET_STATUS_Failure(VKI_ENOMEM);
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return;
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}
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brk_segment_established = True;
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}
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if (new_brk < old_brk_limit) {
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/* Shrinking the data segment. Be lazy and don't munmap the excess
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area. */
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