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>

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index f7625c0952440722c56a3207b10ef7319b16da5d..b05b8b0c6b2199a3a3f764030cbd7d5ae2b0eb45 100644 (file)
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -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);
 

diff --git a/linux-user/sparc/cpu_loop.c b/linux-user/sparc/cpu_loop.c
index ab633eeae3fe63bf80298b143a0c3d3aaf3a91de..0aacda944861a79f4a171345c80a290ea72d6b33 100644 (file)
--- a/linux-user/sparc/cpu_loop.c
+++ b/linux-user/sparc/cpu_loop.c
@@ -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;
 

diff --git a/linux-user/sparc/cpu_loop.h b/linux-user/sparc/cpu_loop.h
new file mode 100644 (file)
index 0000000..fb6e82d
--- /dev/null
+++ b/linux-user/sparc/cpu_loop.h
@@ -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

diff --git a/linux-user/sparc/elfload.c b/linux-user/sparc/elfload.c
index e6387ec891b6a3b90ed4a87ddc61d384c4e0cd1f..181f1e00b59cda93b5184b5d27a6b1a37788606b 100644 (file)
--- a/linux-user/sparc/elfload.c
+++ b/linux-user/sparc/elfload.c
@@ -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
 }

diff --git a/linux-user/sparc/target_elf.h b/linux-user/sparc/target_elf.h
index edb0b3103cbd0d51823426ee408ab9080cca77e7..365af864b0c58599474b970a6211e231f5484819 100644 (file)
--- a/linux-user/sparc/target_elf.h
+++ b/linux-user/sparc/target_elf.h
@@ -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