From 80a56cc3ee45d4a2a1c3ec5e67ff359a7b380fb6 Mon Sep 17 00:00:00 2001 From: Will Newton Date: Mon, 27 Jan 2014 09:01:03 +0000 Subject: ARM: Add SystemTap probes to longjmp and setjmp. Now the ARM port implements pointer encryption for jmpbufs, gdb needs a SystemTap probe point in longjmp to determine the target PC of a call to longjmp. This patch implements the probe point in longjmp and a similar probe point in setjmp. In order to have all the appropriate registers available to pass to the probe this reorders the layout of jmpbuf, putting the sp and lr registers at the start rather than the end, allowing them to be read and written sequentially. Tested on armv7, no new failures in the glibc testsuite and confirmed that this fixes the gdb.base/longjmp.exp failures in the gdb testsuite. ChangeLog: 2014-02-25 Will Newton * sysdeps/arm/__longjmp.S: Include stap-probe.h. (__longjmp): Restore sp and lr before restoring callee saved registers. Add longjmp and longjmp_target SystemTap probe point. * sysdeps/arm/bits/setjmp.h (__jmp_buf): Update comment. * sysdeps/arm/include/bits/setjmp.h (__JMP_BUF_SP): Define to zero to match jmpbuf layout. * sysdeps/arm/setjmp.S: Include stap-probe.h. (__sigsetjmp): Save sp and lr before saving callee saved registers. Add setjmp SystemTap probe point. --- sysdeps/arm/__longjmp.S | 61 ++++++++++++++++++++++++--------------- sysdeps/arm/bits/setjmp.h | 5 ++-- sysdeps/arm/include/bits/setjmp.h | 2 +- sysdeps/arm/setjmp.S | 12 ++++++-- 4 files changed, 49 insertions(+), 31 deletions(-) (limited to 'sysdeps') diff --git a/sysdeps/arm/__longjmp.S b/sysdeps/arm/__longjmp.S index 27c57a12df..08521e5374 100644 --- a/sysdeps/arm/__longjmp.S +++ b/sysdeps/arm/__longjmp.S @@ -17,6 +17,7 @@ . */ #include +#include #include #include #include @@ -25,31 +26,35 @@ ENTRY (__longjmp) mov ip, r0 - movs r0, r1 /* get the return value in place */ - it eq - moveq r0, #1 /* can't let setjmp() return zero! */ #ifdef CHECK_SP sfi_breg ip, \ - ldr r4, [\B, #32] /* jmpbuf's sp */ + ldr r4, [\B] /* jmpbuf's sp */ cfi_undefined (r4) #ifdef PTR_DEMANGLE PTR_DEMANGLE (r4, r4, a3, a4) #endif CHECK_SP (r4) #endif - sfi_sp sfi_breg ip, \ - ldmia \B!, JMP_BUF_REGLIST + #ifdef PTR_DEMANGLE ldr a4, [ip], #4 - PTR_DEMANGLE (a4, a4, a3, a2) - mov sp, a4 - ldr a4, [ip], #4 - PTR_DEMANGLE2 (lr, a4, a3) + PTR_DEMANGLE (a4, a4, a3, r4) + cfi_undefined (r4) + ldr r4, [ip], #4 + PTR_DEMANGLE2 (r4, r4, a3) #else - ldr sp, [ip], #4 - ldr lr, [ip], #4 + ldr a4, [ip], #4 + ldr r4, [ip], #4 + cfi_undefined (r4) #endif + /* longjmp probe expects longjmp first argument (4@r0), second + argument (-4@r1), and target address (4@r4), respectively. */ + LIBC_PROBE (longjmp, 3, 4@r0, -4@r1, 4@r4) + mov sp, a4 + mov lr, r4 + sfi_sp sfi_breg ip, \ + ldmia \B!, JMP_BUF_REGLIST cfi_restore (v1) cfi_restore (v2) cfi_restore (v3) @@ -67,27 +72,27 @@ ENTRY (__longjmp) #ifdef NEED_HWCAP # ifdef IS_IN_rtld - ldr a2, 1f + ldr a4, 1f ldr a3, .Lrtld_local_ro -0: add a2, pc, a2 - add a2, a2, a3 - ldr a2, [a2, #RTLD_GLOBAL_RO_DL_HWCAP_OFFSET] +0: add a4, pc, a4 + add a4, a4, a3 + ldr a4, [a4, #RTLD_GLOBAL_RO_DL_HWCAP_OFFSET] # else # ifdef PIC - ldr a2, 1f + ldr a4, 1f ldr a3, .Lrtld_global_ro -0: add a2, pc, a2 - ldr a2, [a2, a3] - ldr a2, [a2, #RTLD_GLOBAL_RO_DL_HWCAP_OFFSET] +0: add a4, pc, a4 + ldr a4, [a4, a3] + ldr a4, [a4, #RTLD_GLOBAL_RO_DL_HWCAP_OFFSET] # else - ldr a2, .Lhwcap - ldr a2, [a2, #0] + ldr a4, .Lhwcap + ldr a4, [a4, #0] # endif # endif #endif #ifdef __SOFTFP__ - tst a2, #HWCAP_ARM_VFP + tst a4, #HWCAP_ARM_VFP beq .Lno_vfp #endif @@ -98,7 +103,7 @@ ENTRY (__longjmp) .Lno_vfp: #ifndef ARM_ASSUME_NO_IWMMXT - tst a2, #HWCAP_ARM_IWMMXT + tst a4, #HWCAP_ARM_IWMMXT beq .Lno_iwmmxt /* Restore the call-preserved iWMMXt registers. */ @@ -118,6 +123,14 @@ ENTRY (__longjmp) .Lno_iwmmxt: #endif + /* longjmp_target probe expects longjmp first argument (4@r0), second + argument (-4@r1), and target address (4@r14), respectively. */ + LIBC_PROBE (longjmp_target, 3, 4@r0, -4@r1, 4@r14) + + movs r0, r1 /* get the return value in place */ + it eq + moveq r0, #1 /* can't let setjmp() return zero! */ + DO_RET(lr) #ifdef NEED_HWCAP diff --git a/sysdeps/arm/bits/setjmp.h b/sysdeps/arm/bits/setjmp.h index 41423b2c3b..a68735993a 100644 --- a/sysdeps/arm/bits/setjmp.h +++ b/sysdeps/arm/bits/setjmp.h @@ -28,9 +28,8 @@ /* The exact set of registers saved may depend on the particular core in use, as some coprocessor registers may need to be saved. The C Library ABI requires that the buffer be 8-byte aligned, and - recommends that the buffer contain 64 words. The first 27 words - are occupied by v1-v6, sl, fp, sp, pc, and d8-d15. (Note that - d8-15 require 17 words, due to the use of fstmx.) */ + recommends that the buffer contain 64 words. The first 26 words + are occupied by sp, lr, v1-v6, sl, fp, and d8-d15. */ typedef int __jmp_buf[64] __attribute__((__aligned__ (8))); #endif diff --git a/sysdeps/arm/include/bits/setjmp.h b/sysdeps/arm/include/bits/setjmp.h index 220dfe8d96..5877c1f659 100644 --- a/sysdeps/arm/include/bits/setjmp.h +++ b/sysdeps/arm/include/bits/setjmp.h @@ -30,7 +30,7 @@ # define JMP_BUF_REGLIST {v1-v6, sl, fp} /* Index of __jmp_buf where the sp register resides. */ -# define __JMP_BUF_SP 8 +# define __JMP_BUF_SP 0 #endif #endif /* include/bits/setjmp.h */ diff --git a/sysdeps/arm/setjmp.S b/sysdeps/arm/setjmp.S index b0b45ed8da..5e55ca5061 100644 --- a/sysdeps/arm/setjmp.S +++ b/sysdeps/arm/setjmp.S @@ -17,6 +17,7 @@ . */ #include +#include #include #include #include @@ -27,9 +28,11 @@ ENTRY (__sigsetjmp) #endif mov ip, r0 - /* Save registers */ - sfi_breg ip, \ - stmia \B!, JMP_BUF_REGLIST + /* setjmp probe expects sigsetjmp first argument (4@r0), second + argument (-4@r1), and target address (4@r14), respectively. */ + LIBC_PROBE (setjmp, 3, 4@r0, -4@r1, 4@r14) + + /* Save sp and lr */ #ifdef PTR_MANGLE mov a4, sp PTR_MANGLE2 (a4, a4, a3) @@ -40,6 +43,9 @@ ENTRY (__sigsetjmp) str sp, [ip], #4 str lr, [ip], #4 #endif + /* Save registers */ + sfi_breg ip, \ + stmia \B!, JMP_BUF_REGLIST #if !defined ARM_ASSUME_NO_IWMMXT || defined __SOFTFP__ # define NEED_HWCAP 1 -- cgit 1.4.1