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linux-user/sparc: flush register windows before core dump

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Without this, only the crash frame's window is spilled to the
stack; all deeper call frames remain in the register file and
are absent from the core's memory segments. Stack unwinding
fails past the first DWARF step because the callers' register
save areas contain stale/garbage data.

The real kernel calls flush_all_user_windows() at the top of
do_coredump(). Mirror that via a weak target_flush_windows()
hook called from dump_core_and_abort(), with the SPARC override
calling the existing flush_windows() in cpu_loop.c.

Signed-off-by: Matt Turner <mattst88@gmail.com>
Cc: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Helge Deller <deller@gmx.de>
This commit is contained in:
Matt Turner
2026-06-03 20:30:59 -04:00
committed by Helge Deller
parent e0f0ce88eb
commit f83f550549
5 changed files with 64 additions and 11 deletions
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9
linux-user/elfload.c
View File

@@ -2445,6 +2445,9 @@ static int wmr_write_region(void *opaque, vaddr start,
* handler (provided that target process haven't registered
* handler for that) that does the dump when signal is received.
*/
#ifdef TARGET_SPARC
#include "sparc/cpu_loop.h"
#endif
static int elf_core_dump(int signr, const CPUArchState *env)
{
const CPUState *cpu = env_cpu_const(env);
@@ -2468,6 +2471,12 @@ static int elf_core_dump(int signr, const CPUArchState *env)
cpu_list_lock();
mmap_lock();
#ifdef TARGET_SPARC
CPU_FOREACH(cpu_iter) {
flush_windows(cpu_env(cpu_iter));
}
#endif
/* By unprotecting, we merge vmas that might be split. */
walk_memory_regions(NULL, wmr_page_unprotect_regions);

3
linux-user/sparc/cpu_loop.c
View File

@@ -22,6 +22,7 @@
#include "user-internals.h"
#include "user/cpu_loop.h"
#include "signal-common.h"
#include "sparc/cpu_loop.h"
#define SPARC64_STACK_BIAS 2047
@@ -119,7 +120,7 @@ static void restore_window(CPUSPARCState *env)
#endif
}
static void flush_windows(CPUSPARCState *env)
void flush_windows(CPUSPARCState *env)
{
int offset, cwp1;

7
linux-user/sparc/cpu_loop.h Normal file
View File

@@ -0,0 +1,7 @@
/* SPDX-License-Identifier: GPL-2.0-or-later */
#ifndef SPARC_CPU_LOOP_H
#define SPARC_CPU_LOOP_H
void flush_windows(CPUSPARCState *env);
#endif

39
linux-user/sparc/elfload.c
View File

@@ -12,16 +12,41 @@ void elf_core_copy_regs(target_elf_gregset_t *r, const CPUArchState *env)
CPUSPARCState *e = (CPUSPARCState *)env;
int i;
memset(r, 0, sizeof(*r));
#if defined(TARGET_SPARC64) && !defined(TARGET_ABI32)
/* Linux kernel layout for sparc64 (arch/sparc/include/asm/elf_64.h):
* [0..7] G0-G7
* [8..15] O0-O7
* [16..23] L0-L7
* [24..31] I0-I7
* [32] TSTATE
* [33] TPC
* [34] TNPC
* [35] Y
*/
for (i = 0; i < 8; i++) {
r->regs[i] = tswap64(env->gregs[i]);
r->regs[8 + i] = tswap64(env->regwptr[WREG_O0 + i]);
r->regs[i] = tswap64(env->gregs[i]);
r->regs[8 + i] = tswap64(env->regwptr[WREG_O0 + i]);
r->regs[16 + i] = tswap64(env->regwptr[WREG_L0 + i]);
r->regs[24 + i] = tswap64(env->regwptr[WREG_I0 + i]);
}
r->regs[16] = tswap64(sparc64_tstate(e));
r->regs[17] = tswap64(env->pc);
r->regs[18] = tswap64(env->npc);
r->regs[19] = tswap64(env->y);
r->regs[32] = tswap64(sparc64_tstate(e));
r->regs[33] = tswap64(env->pc);
r->regs[34] = tswap64(env->npc);
r->regs[35] = tswap64(env->y);
#else
/* Linux kernel layout for sparc32 (arch/sparc/include/asm/elf_32.h):
* [0] PSR
* [1] PC
* [2] NPC
* [3] Y
* [4..11] G0-G7
* [12..19] O0-O7
* [20..27] L0-L7
* [28..35] I0-I7
* [36..37] reserved (stack_check)
*/
r->regs[0] = tswap32(cpu_get_psr(e));
r->regs[1] = tswap32(env->pc);
r->regs[2] = tswap32(env->npc);
@@ -29,6 +54,8 @@ void elf_core_copy_regs(target_elf_gregset_t *r, const CPUArchState *env)
for (i = 0; i < 8; i++) {
r->regs[4 + i] = tswap32(env->gregs[i]);
r->regs[12 + i] = tswap32(env->regwptr[WREG_O0 + i]);
r->regs[20 + i] = tswap32(env->regwptr[WREG_L0 + i]);
r->regs[28 + i] = tswap32(env->regwptr[WREG_I0 + i]);
}
#endif
}

17
linux-user/sparc/target_elf.h
View File

@@ -24,12 +24,21 @@
#define HAVE_ELF_CORE_DUMP 1
/*
* Matches the kernel's elf_gregset_t (ELF_NGREG = 20).
* sparc32/sparc32plus: psr, pc, npc, y, u_regs[16] (g0-g7, o0-o7)
* sparc64: u_regs[16] (g0-g7, o0-o7), tstate, pc, npc, y
* Matches the kernel's elf_gregset_t.
* sparc32/sparc32plus (ELF_NGREG = 38):
* psr, pc, npc, y, u_regs[16] (g0-g7, o0-o7),
* reg_window[16] (l0-l7, i0-i7), stack_check[2]
* sparc64 (ELF_NGREG = 36):
* u_regs[16] (g0-g7, o0-o7), reg_window[16] (l0-l7, i0-i7),
* tstate, tpc, tnpc, y
*/
#if defined(TARGET_SPARC64) && !defined(TARGET_ABI32)
# define TARGET_ELF_NGREG 36
#else
# define TARGET_ELF_NGREG 38
#endif
typedef struct target_elf_gregset_t {
abi_ulong regs[20];
abi_ulong regs[TARGET_ELF_NGREG];
} target_elf_gregset_t;
#endif