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mips: remote unwind support

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libunwind already had support for local unwind on a MIPS. This patch makes
support for remote unwinding on a MIPS.

I should add a few words to the changes to _UPT_access_mem.c: On MIPS, an
unw_word_t is defined as a 64-bit integer whether it's compiled for a 32- or a
64-bit MIPS.

When doing remote unwinding using the default _UPT_accessors, dwarf_readu8()
therefore expects _UPT_access_mem() to return a 64-bit integer. However, if
compiled on a 32-bit MIPS, only 32 bits are valid upon return from
_UPT_access_mem(). The patch detects this and will in this case perform two
calls to ptrace(PTRACE_POKE/PEEK_DATA) and organize the return value according
to endianness.
This commit is contained in:
Rene Nielsen 2016-08-12 07:13:35 +00:00 committed by Dave Watson
parent 54a970079d
commit 2a5d1a6296
3 changed files with 86 additions and 20 deletions
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4
include/libunwind-mips.h
View File

@ -30,7 +30,7 @@ extern "C" {
#endif
#include <inttypes.h>
#include <ucontext.h>
#include <sys/ucontext.h>
#ifdef mips
# undef mips
@ -103,7 +103,7 @@ typedef enum
previous frame. */
UNW_MIPS_CFA,
UNW_TDEP_LAST_REG = UNW_MIPS_R31,
UNW_TDEP_LAST_REG = UNW_MIPS_PC,
UNW_TDEP_IP = UNW_MIPS_R31,
UNW_TDEP_SP = UNW_MIPS_R29,

41
src/ptrace/_UPT_access_mem.c
View File

@ -32,19 +32,41 @@ _UPT_access_mem (unw_addr_space_t as, unw_word_t addr, unw_word_t *val,
int write, void *arg)
{
struct UPT_info *ui = arg;
int i, end;
unw_word_t tmp_val;
if (!ui)
return -UNW_EINVAL;
pid_t pid = ui->pid;
// Some 32-bit archs have to define a 64-bit unw_word_t.
// Callers of this function therefore expect a 64-bit
// return value, but ptrace only returns a 32-bit value
// in such cases.
if (sizeof(long) == 4 && sizeof(unw_word_t) == 8)
end = 2;
else
end = 1;
for (i = 0; i < end; i++)
{
unw_word_t tmp_addr = i == 0 ? addr : addr + 4;
errno = 0;
if (write)
{
Debug (16, "mem[%lx] <- %lx\n", (long) addr, (long) *val);
#if __BYTE_ORDER == __LITTLE_ENDIAN
tmp_val = i == 0 ? *val : *val >> 32;
#else
tmp_val = i == 0 && end == 2 ? *val >> 32 : *val;
#endif
Debug (16, "mem[%lx] <- %lx\n", (long) tmp_addr, (long) tmp_val);
#ifdef HAVE_TTRACE
# warning No support for ttrace() yet.
#else
ptrace (PTRACE_POKEDATA, pid, addr, *val);
ptrace (PTRACE_POKEDATA, pid, tmp_addr, tmp_val);
if (errno)
return -UNW_EINVAL;
#endif
@ -54,11 +76,22 @@ _UPT_access_mem (unw_addr_space_t as, unw_word_t addr, unw_word_t *val,
#ifdef HAVE_TTRACE
# warning No support for ttrace() yet.
#else
*val = ptrace (PTRACE_PEEKDATA, pid, addr, 0);
tmp_val = (unsigned long) ptrace (PTRACE_PEEKDATA, pid, tmp_addr, 0);
if (i == 0)
*val = 0;
#if __BYTE_ORDER == __LITTLE_ENDIAN
*val |= tmp_val << (i * 32);
#else
*val |= i == 0 && end == 2 ? tmp_val << 32 : tmp_val;
#endif
if (errno)
return -UNW_EINVAL;
#endif
Debug (16, "mem[%lx] -> %lx\n", (long) addr, (long) *val);
Debug (16, "mem[%lx] -> %lx\n", (long) tmp_addr, (long) tmp_val);
}
}
return 0;
}

33
src/ptrace/_UPT_reg_offset.c
View File

@ -501,6 +501,39 @@ const int _UPT_reg_offset[UNW_REG_LAST + 1] =
[UNW_ARM_R14] = 0x38,
[UNW_ARM_R15] = 0x3c,
#elif defined(UNW_TARGET_MIPS)
[UNW_MIPS_R0] = 0,
[UNW_MIPS_R1] = 1,
[UNW_MIPS_R2] = 2,
[UNW_MIPS_R3] = 3,
[UNW_MIPS_R4] = 4,
[UNW_MIPS_R5] = 5,
[UNW_MIPS_R6] = 6,
[UNW_MIPS_R7] = 7,
[UNW_MIPS_R8] = 8,
[UNW_MIPS_R9] = 9,
[UNW_MIPS_R10] = 10,
[UNW_MIPS_R11] = 11,
[UNW_MIPS_R12] = 12,
[UNW_MIPS_R13] = 13,
[UNW_MIPS_R14] = 14,
[UNW_MIPS_R15] = 15,
[UNW_MIPS_R16] = 16,
[UNW_MIPS_R17] = 17,
[UNW_MIPS_R18] = 18,
[UNW_MIPS_R19] = 19,
[UNW_MIPS_R20] = 20,
[UNW_MIPS_R21] = 21,
[UNW_MIPS_R22] = 22,
[UNW_MIPS_R23] = 23,
[UNW_MIPS_R24] = 24,
[UNW_MIPS_R25] = 25,
[UNW_MIPS_R26] = 26,
[UNW_MIPS_R27] = 27,
[UNW_MIPS_R28] = 28,
[UNW_MIPS_R29] = 29,
[UNW_MIPS_R30] = 30,
[UNW_MIPS_R31] = 31,
[UNW_MIPS_PC] = 64,
#elif defined(UNW_TARGET_SH)
#elif defined(UNW_TARGET_AARCH64)
[UNW_AARCH64_X0] = 0x00,