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authorA. Wilcox <AWilcox@Wilcox-Tech.com>2018-11-24 08:35:09 +0000
committerA. Wilcox <AWilcox@Wilcox-Tech.com>2018-11-24 08:35:09 +0000
commitf827eb8f60d926607ee409dbbc93159a1e52c4d6 (patch)
tree35d4bf7d020cc83f0fcdd6826431dca6dfbc425b /system/musl/dynamic-binary-stack-size.patch
parent92fb930d4fcbdd4ec0996210c9323ce38d567efd (diff)
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system/musl: add ability to add default stack size to binaries
Diffstat (limited to 'system/musl/dynamic-binary-stack-size.patch')
-rw-r--r--system/musl/dynamic-binary-stack-size.patch97
1 files changed, 97 insertions, 0 deletions
diff --git a/system/musl/dynamic-binary-stack-size.patch b/system/musl/dynamic-binary-stack-size.patch
new file mode 100644
index 000000000..e2e3f12d3
--- /dev/null
+++ b/system/musl/dynamic-binary-stack-size.patch
@@ -0,0 +1,97 @@
+From 7b3348a98c139b4b4238384e52d4b0eb237e4833 Mon Sep 17 00:00:00 2001
+From: Rich Felker <dalias@aerifal.cx>
+Date: Tue, 18 Sep 2018 23:54:18 -0400
+Subject: support setting of default thread stack size via PT_GNU_STACK header
+
+this facilitates building software that assumes a large default stack
+size without any patching to call pthread_setattr_default_np or
+pthread_attr_setstacksize at each thread creation site, using just
+LDFLAGS.
+
+normally the PT_GNU_STACK header is used only to reflect whether
+executable stack is desired, but with GNU ld at least, passing
+-Wl,-z,stack-size=N will set a size on the program header. with this
+patch, that size will be incorporated into the default stack size
+(subject to increase-only rule and DEFAULT_STACK_MAX limit).
+
+both static and dynamic linking honor the program header. for dynamic
+linking, all libraries loaded at program start, including preloaded
+ones, are considered. dlopened libraries are not considered, for
+several reasons. extra logic would be needed to defer processing until
+the load of the new library is commited, synchronization woud be
+needed since other threads may be running concurrently, and the
+effectiveness woud be limited since the larger size would not apply to
+threads that already existed at the time of dlopen. programs that will
+dlopen code expecting a large stack need to declare the requirement
+themselves, or pthread_setattr_default_np can be used.
+---
+ ldso/dynlink.c | 12 ++++++++++++
+ src/env/__init_tls.c | 5 +++++
+ 2 files changed, 17 insertions(+)
+
+diff --git a/ldso/dynlink.c b/ldso/dynlink.c
+index e4829c3a..3ecbddfa 100644
+--- a/ldso/dynlink.c
++++ b/ldso/dynlink.c
+@@ -22,6 +22,7 @@
+ #include "dynlink.h"
+
+ static void error(const char *, ...);
++extern size_t __default_stacksize;
+
+ #define MAXP2(a,b) (-(-(a)&-(b)))
+ #define ALIGN(x,y) ((x)+(y)-1 & -(y))
+@@ -609,6 +610,12 @@ static void *map_library(int fd, struct dso *dso)
+ } else if (ph->p_type == PT_GNU_RELRO) {
+ dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
+ dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
++ } else if (ph->p_type == PT_GNU_STACK) {
++ if (!runtime && ph->p_memsz > __default_stacksize) {
++ __default_stacksize =
++ ph->p_memsz < (8<<20) ?
++ ph->p_memsz : (8<<20);
++ }
+ }
+ if (ph->p_type != PT_LOAD) continue;
+ nsegs++;
+@@ -1238,6 +1245,12 @@ static void kernel_mapped_dso(struct dso *p)
+ } else if (ph->p_type == PT_GNU_RELRO) {
+ p->relro_start = ph->p_vaddr & -PAGE_SIZE;
+ p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
++ } else if (ph->p_type == PT_GNU_STACK) {
++ if (!runtime && ph->p_memsz > __default_stacksize) {
++ __default_stacksize =
++ ph->p_memsz < (8<<20) ?
++ ph->p_memsz : (8<<20);
++ }
+ }
+ if (ph->p_type != PT_LOAD) continue;
+ if (ph->p_vaddr < min_addr)
+diff --git a/src/env/__init_tls.c b/src/env/__init_tls.c
+index e0224243..96d0e284 100644
+--- a/src/env/__init_tls.c
++++ b/src/env/__init_tls.c
+@@ -8,6 +8,8 @@
+ #include "atomic.h"
+ #include "syscall.h"
+
++extern size_t __default_stacksize;
++
+ int __init_tp(void *p)
+ {
+ pthread_t td = p;
+@@ -90,6 +91,11 @@ static void static_init_tls(size_t *aux)
+ base = (size_t)_DYNAMIC - phdr->p_vaddr;
+ if (phdr->p_type == PT_TLS)
+ tls_phdr = phdr;
++ if (phdr->p_type == PT_GNU_STACK &&
++ phdr->p_memsz > __default_stacksize)
++ __default_stacksize =
++ phdr->p_memsz < (8<<20) ?
++ phdr->p_memsz : (8<<20);
+ }
+
+ if (tls_phdr) {
+--
+cgit v1.2.1
+