linux-user/sparc: flush register windows before core dump
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>
Matt Turner committed
Jun 3, 2026 at 20:30 UTC
f83f5505497c2b2b08a9bc9a3bd5aee2df5fa7ca
5 files changed
+64
-11
linux-user/elfload.c
+9
@@ -2445,6 +2445,9 @@ static int wmr_write_region(void *opaque, vaddr start,
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* handler (provided that target process haven't registered
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* handler for that) that does the dump when signal is received.
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*/
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+#ifdef TARGET_SPARC
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+#include "sparc/cpu_loop.h"
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+#endif
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static int elf_core_dump(int signr, const CPUArchState *env)
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{
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const CPUState *cpu = env_cpu_const(env);
@@ -2468,6 +2471,12 @@ static int elf_core_dump(int signr, const CPUArchState *env)
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cpu_list_lock();
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mmap_lock();
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+#ifdef TARGET_SPARC
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+ CPU_FOREACH(cpu_iter) {
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+ flush_windows(cpu_env(cpu_iter));
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+ }
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+#endif
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+
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/* By unprotecting, we merge vmas that might be split. */
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walk_memory_regions(NULL, wmr_page_unprotect_regions);
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linux-user/sparc/cpu_loop.c
+2
-1
@@ -22,6 +22,7 @@
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#include "user-internals.h"
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#include "user/cpu_loop.h"
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#include "signal-common.h"
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+#include "sparc/cpu_loop.h"
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#define SPARC64_STACK_BIAS 2047
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@@ -119,7 +120,7 @@ static void restore_window(CPUSPARCState *env)
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#endif
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}
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-static void flush_windows(CPUSPARCState *env)
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+void flush_windows(CPUSPARCState *env)
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{
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int offset, cwp1;
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linux-user/sparc/cpu_loop.h
new
+7
@@ -0,0 +1,7 @@
1
+/* SPDX-License-Identifier: GPL-2.0-or-later */
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+#ifndef SPARC_CPU_LOOP_H
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+#define SPARC_CPU_LOOP_H
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+
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+void flush_windows(CPUSPARCState *env);
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+
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+#endif
linux-user/sparc/elfload.c
+33
-6
@@ -12,16 +12,41 @@ void elf_core_copy_regs(target_elf_gregset_t *r, const CPUArchState *env)
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CPUSPARCState *e = (CPUSPARCState *)env;
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int i;
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+ memset(r, 0, sizeof(*r));
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+
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#if defined(TARGET_SPARC64) && !defined(TARGET_ABI32)
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+ /* Linux kernel layout for sparc64 (arch/sparc/include/asm/elf_64.h):
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+ * [0..7] G0-G7
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+ * [8..15] O0-O7
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+ * [16..23] L0-L7
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+ * [24..31] I0-I7
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+ * [32] TSTATE
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+ * [33] TPC
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+ * [34] TNPC
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+ * [35] Y
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+ */
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for (i = 0; i < 8; i++) {
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- r->regs[i] = tswap64(env->gregs[i]);
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- r->regs[8 + i] = tswap64(env->regwptr[WREG_O0 + i]);
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+ r->regs[i] = tswap64(env->gregs[i]);
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+ r->regs[8 + i] = tswap64(env->regwptr[WREG_O0 + i]);
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+ r->regs[16 + i] = tswap64(env->regwptr[WREG_L0 + i]);
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+ r->regs[24 + i] = tswap64(env->regwptr[WREG_I0 + i]);
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}
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- r->regs[16] = tswap64(sparc64_tstate(e));
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- r->regs[17] = tswap64(env->pc);
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- r->regs[18] = tswap64(env->npc);
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- r->regs[19] = tswap64(env->y);
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+ r->regs[32] = tswap64(sparc64_tstate(e));
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+ r->regs[33] = tswap64(env->pc);
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+ r->regs[34] = tswap64(env->npc);
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+ r->regs[35] = tswap64(env->y);
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#else
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+ /* Linux kernel layout for sparc32 (arch/sparc/include/asm/elf_32.h):
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+ * [0] PSR
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+ * [1] PC
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+ * [2] NPC
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+ * [3] Y
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+ * [4..11] G0-G7
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+ * [12..19] O0-O7
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+ * [20..27] L0-L7
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+ * [28..35] I0-I7
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+ * [36..37] reserved (stack_check)
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+ */
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r->regs[0] = tswap32(cpu_get_psr(e));
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r->regs[1] = tswap32(env->pc);
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r->regs[2] = tswap32(env->npc);
@@ -29,6 +54,8 @@ void elf_core_copy_regs(target_elf_gregset_t *r, const CPUArchState *env)
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for (i = 0; i < 8; i++) {
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r->regs[4 + i] = tswap32(env->gregs[i]);
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r->regs[12 + i] = tswap32(env->regwptr[WREG_O0 + i]);
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+ r->regs[20 + i] = tswap32(env->regwptr[WREG_L0 + i]);
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+ r->regs[28 + i] = tswap32(env->regwptr[WREG_I0 + i]);
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}
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#endif
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}
linux-user/sparc/target_elf.h
+13
-4
@@ -24,12 +24,21 @@
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#define HAVE_ELF_CORE_DUMP 1
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/*
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- * Matches the kernel's elf_gregset_t (ELF_NGREG = 20).
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- * sparc32/sparc32plus: psr, pc, npc, y, u_regs[16] (g0-g7, o0-o7)
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- * sparc64: u_regs[16] (g0-g7, o0-o7), tstate, pc, npc, y
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+ * Matches the kernel's elf_gregset_t.
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+ * sparc32/sparc32plus (ELF_NGREG = 38):
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+ * psr, pc, npc, y, u_regs[16] (g0-g7, o0-o7),
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+ * reg_window[16] (l0-l7, i0-i7), stack_check[2]
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+ * sparc64 (ELF_NGREG = 36):
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+ * u_regs[16] (g0-g7, o0-o7), reg_window[16] (l0-l7, i0-i7),
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+ * tstate, tpc, tnpc, y
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*/
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+#if defined(TARGET_SPARC64) && !defined(TARGET_ABI32)
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+# define TARGET_ELF_NGREG 36
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+#else
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+# define TARGET_ELF_NGREG 38
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+#endif
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typedef struct target_elf_gregset_t {
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- abi_ulong regs[20];
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+ abi_ulong regs[TARGET_ELF_NGREG];
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} target_elf_gregset_t;
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#endif