diff options
| author | Dale Rahn <drahn@cvs.openbsd.org> | 2009-06-16 16:37:15 +0000 |
|---|---|---|
| committer | Dale Rahn <drahn@cvs.openbsd.org> | 2009-06-16 16:37:15 +0000 |
| commit | a3f40e2b55539a27c6990efc4ebff8036b9a4938 (patch) | |
| tree | c4eb37fc3c701dd46cc8f1fc9cad913bb46daa58 | |
| parent | 91b80125303d8d8b8dcdfd29969a3b360546c468 (diff) | |
Do not break gcc -Z on powerpc. mprotect the got only if it is padded.
Diff written and tweaked by kurt@ and myself.
ok kurt@, now is agood time deraadt@
| -rw-r--r-- | lib/csu/powerpc/crt0.c | 49 |
1 files changed, 34 insertions, 15 deletions
diff --git a/lib/csu/powerpc/crt0.c b/lib/csu/powerpc/crt0.c index 2d2f9104114..e3e1c11eb2a 100644 --- a/lib/csu/powerpc/crt0.c +++ b/lib/csu/powerpc/crt0.c @@ -1,4 +1,4 @@ -/* $OpenBSD: crt0.c,v 1.4 2009/01/14 19:45:20 kurt Exp $ */ +/* $OpenBSD: crt0.c,v 1.5 2009/06/16 16:37:14 drahn Exp $ */ /* $NetBSD: crt0.c,v 1.1 1996/09/12 16:59:02 cgd Exp $ */ /* * Copyright (c) 1995 Christopher G. Demetriou @@ -52,10 +52,16 @@ __asm( " .text \n" " .section \".text\" \n" " .align 2 \n" -" .globl _start \n" -" .type _start, @function \n" -" .globl __start \n" -" .type __start, @function \n" +" .size __got_start, 0 \n" +" .type __got_start, @object \n" +" .size __got_end, 0 \n" +" .type __got_end, @object \n" +" .weak __got_start \n" +" .weak __got_end \n" +" .globl _start \n" +" .type _start, @function \n" +" .globl __start \n" +" .type __start, @function \n" "_start: \n" "__start: \n" " # move argument registers to saved registers for startup flush \n" @@ -70,8 +76,8 @@ __asm( " # to find the virtual address where the page is loaded. \n" " bl _GLOBAL_OFFSET_TABLE_@local-4 \n" "1: \n" -" mflr %r5 # this stores where we are (+4) \n" -" lwz %r18, 0(%r5) # load the instruction at offset_sym \n" +" mflr %r6 # this stores where we are (+4) \n" +" lwz %r18, 0(%r6) # load the instruction at offset_sym \n" " # it contains an offset to the location \n" " # of the GOT. \n" " \n" @@ -82,25 +88,38 @@ __asm( " * bl _GLOBAL_OFFSET_TABLE_@local-4 \n" " * operation that would be below would calulate. \n" " */ \n" -" add %r28, %r18, %r5 \n" -" mr %r6, %r5 # save offset for later use \n" +" add %r28, %r18, %r6 \n" " \n" -" /* mprotect GOT-4 for correct execution of blrl instruction */ \n" +" addi %r3,%r28,4 # calculate the actual got addr \n" +" lwz %r0,__got_start@got(%r3) \n" +" cmpwi %r0,0 \n" +" beq 4f \n" +" cmpw %r0,%r28 \n" +" bne 4f \n" +" lwz %r4,__got_end@got(%r3) \n" +" cmpwi %r4,0 \n" +" beq 2f \n" +" \n" +" sub %r4, %r4, %r0 \n" +" b 3f \n" +"2: \n" +" li %r4, 4 \n" +"3: \n" +" \n" +" /* mprotect GOT to eliminate W+X regions in static binaries */ \n" " li %r0, " STR(SYS_mprotect) " \n" " mr %r3, %r28 \n" -" li %r4, 4 \n" " li %r5, 5 /* (PROT_READ|PROT_EXEC) */ \n" " sc \n" " \n" -" mr %r5, %r6 \n" -" \n" +"4: \n" " li %r0, 0 \n" " # flush the blrl instruction out of the data cache \n" -" dcbf %r5, %r18 \n" +" dcbf %r6, %r18 \n" " sync \n" " isync \n" " # make certain that the got table addr is not in the icache \n" -" icbi %r5, %r18 \n" +" icbi %r6, %r18 \n" " sync \n" " isync \n" " mtlr %r27 \n" |