[PATCH 1/5] linux-user/alpha: write the floating-point registers to a core dump

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* [PATCH 1/5] linux-user/alpha: write the floating-point registers to a core dump
@ 2026-08-05 17:15 Matt Turner
  2026-08-05 17:15 ` [PATCH 2/5] linux-user/mips: " Matt Turner
                   ` (4 more replies)
  0 siblings, 5 replies; 6+ messages in thread
From: Matt Turner @ 2026-08-05 17:15 UTC (permalink / raw)
  To: qemu-devel; +Cc: Matt Turner, Laurent Vivier, Helge Deller, Pierrick Bouvier

A guest core carried only the general-purpose registers, so a debugger
opening one reported every floating-point register as unavailable --
including the arguments of the function that crashed.

Implement HAVE_ELF_CORE_FPREGS for Alpha: define target_elf_fpregset_t
to match the kernel's layout ($f0-$f30 plus the control register in the
slot $f31 would occupy) and fill it from elf_core_copy_fpregs().

Checked with lldb on a core from a program that faults with live values
in $f16 and $f17: both read back correctly, as does the control register.

Signed-off-by: Matt Turner <mattst88@gmail.com>
---
 linux-user/alpha/elfload.c    | 10 ++++++++++
 linux-user/alpha/target_elf.h | 11 +++++++++++
 2 files changed, 21 insertions(+)

diff --git ./linux-user/alpha/elfload.c ./linux-user/alpha/elfload.c
index 7be9e466b6..c2517516ad 100644
--- ./linux-user/alpha/elfload.c
+++ ./linux-user/alpha/elfload.c
@@ -32,3 +32,13 @@ const char *get_elf_cpu_model(uint32_t eflags)
 {
     return "ev67";
 }
+
+void elf_core_copy_fpregs(target_elf_fpregset_t *r, const CPUAlphaState *env)
+{
+    int i;
+
+    for (i = 0; i < 31; i++) {
+        r->fpr[i] = tswap64(env->fir[i]);
+    }
+    r->fpcr = tswap64(cpu_alpha_load_fpcr((CPUAlphaState *)env));
+}
diff --git ./linux-user/alpha/target_elf.h ./linux-user/alpha/target_elf.h
index dd90c6f783..5efe7f3174 100644
--- ./linux-user/alpha/target_elf.h
+++ ./linux-user/alpha/target_elf.h
@@ -19,6 +19,17 @@
  *   r0-r30 at indices 0-30, pc at 31, ps at 32.
  * r31 (hardwired zero) is not stored; pc occupies index 31.
  */
+/*
+ * The floating-point note holds $f0 through $f30 and then the control
+ * register in the slot $f31 would occupy; $f31 reads as zero.
+ */
+#define HAVE_ELF_CORE_FPREGS    1
+
+typedef struct target_elf_fpregset_t {
+    uint64_t fpr[31];    /* $f0-$f30 */
+    uint64_t fpcr;       /* the slot for $f31 */
+} target_elf_fpregset_t;
+
 typedef struct target_elf_gregset_t {
     abi_ulong regs[31];  /* integer registers r0-r30  [0..30] */
     abi_ulong pc;        /* program counter           [31]    */
-- 
2.54.0



^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH 2/5] linux-user/mips: write the floating-point registers to a core dump
  2026-08-05 17:15 [PATCH 1/5] linux-user/alpha: write the floating-point registers to a core dump Matt Turner
@ 2026-08-05 17:15 ` Matt Turner
  2026-08-05 17:15 ` [PATCH 3/5] linux-user/hppa: " Matt Turner
                   ` (3 subsequent siblings)
  4 siblings, 0 replies; 6+ messages in thread
From: Matt Turner @ 2026-08-05 17:15 UTC (permalink / raw)
  To: qemu-devel
  Cc: Matt Turner, Laurent Vivier, Helge Deller, Pierrick Bouvier,
	Philippe Mathieu-Daudé, Jiaxun Yang

Write an NT_FPREGSET note for MIPS and MIPS64, matching the kernel's
elf_fpregset_t layout (ELF_NFPREG = 33): fpr[0..31] hold f0-f31, and
fcsr occupies the low 32 bits of slot 32.  The pad field rounds the
struct to 33 × 8 bytes = 264 bytes.

Signed-off-by: Matt Turner <mattst88@gmail.com>
---
 linux-user/mips/elfload.c      |  8 ++++++++
 linux-user/mips/target_elf.h   | 13 +++++++++++++
 linux-user/mips64/target_elf.h | 13 +++++++++++++
 3 files changed, 34 insertions(+)

diff --git ./linux-user/mips/elfload.c ./linux-user/mips/elfload.c
index ce2c4514f3..1d62ae0a4d 100644
--- ./linux-user/mips/elfload.c
+++ ./linux-user/mips/elfload.c
@@ -130,6 +130,14 @@ const char *get_elf_base_platform(CPUState *cs)
 
 #undef MATCH_PLATFORM_INSN
 
+void elf_core_copy_fpregs(target_elf_fpregset_t *r, const CPUMIPSState *env)
+{
+    for (int i = 0; i < 32; i++) {
+        r->fpr[i] = tswap64(env->active_fpu.fpr[i].d);
+    }
+    r->fcsr = tswap32(env->active_fpu.fcr31);
+}
+
 /* See linux kernel: arch/mips/kernel/process.c:elf_dump_regs.  */
 #ifndef TARGET_MIPS64
 void elf_core_copy_regs(target_elf_gregset_t *r, const CPUMIPSState *env)
diff --git ./linux-user/mips/target_elf.h ./linux-user/mips/target_elf.h
index 157306f7a0..426f905d3a 100644
--- ./linux-user/mips/target_elf.h
+++ ./linux-user/mips/target_elf.h
@@ -26,4 +26,17 @@ typedef struct target_elf_gregset_t {
     };
 } target_elf_gregset_t;
 
+#define HAVE_ELF_CORE_FPREGS    1
+
+/*
+ * Matches the kernel's elf_fpregset_t (ELF_NFPREG = 33):
+ *   fpr[0..31] hold f0-f31; fcsr occupies the low 32 bits of slot 32.
+ *   pad rounds the struct to 33 × 8 bytes = 264 bytes.
+ */
+typedef struct target_elf_fpregset_t {
+    uint64_t fpr[32];
+    uint32_t fcsr;
+    uint32_t pad;
+} target_elf_fpregset_t;
+
 #endif
diff --git ./linux-user/mips64/target_elf.h ./linux-user/mips64/target_elf.h
index 061471a0f1..efb5d97563 100644
--- ./linux-user/mips64/target_elf.h
+++ ./linux-user/mips64/target_elf.h
@@ -32,4 +32,17 @@ typedef struct target_elf_gregset_t {
     };
 } target_elf_gregset_t;
 
+#define HAVE_ELF_CORE_FPREGS    1
+
+/*
+ * Matches the kernel's elf_fpregset_t (ELF_NFPREG = 33):
+ *   fpr[0..31] hold f0-f31; fcsr occupies the low 32 bits of slot 32.
+ *   pad rounds the struct to 33 × 8 bytes = 264 bytes.
+ */
+typedef struct target_elf_fpregset_t {
+    uint64_t fpr[32];
+    uint32_t fcsr;
+    uint32_t pad;
+} target_elf_fpregset_t;
+
 #endif
-- 
2.54.0



^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH 3/5] linux-user/hppa: write the floating-point registers to a core dump
  2026-08-05 17:15 [PATCH 1/5] linux-user/alpha: write the floating-point registers to a core dump Matt Turner
  2026-08-05 17:15 ` [PATCH 2/5] linux-user/mips: " Matt Turner
@ 2026-08-05 17:15 ` Matt Turner
  2026-08-05 17:15 ` [PATCH 4/5] linux-user/riscv: " Matt Turner
                   ` (2 subsequent siblings)
  4 siblings, 0 replies; 6+ messages in thread
From: Matt Turner @ 2026-08-05 17:15 UTC (permalink / raw)
  To: qemu-devel; +Cc: Matt Turner, Laurent Vivier, Helge Deller, Pierrick Bouvier

Write an NT_FPREGSET note for HPPA, matching the kernel's
elf_fpregset_t layout (ELF_NFPREG = 32): fr0-fr31 as 64-bit values.

Signed-off-by: Matt Turner <mattst88@gmail.com>
---
 linux-user/hppa/elfload.c    | 7 +++++++
 linux-user/hppa/target_elf.h | 9 +++++++++
 2 files changed, 16 insertions(+)

diff --git ./linux-user/hppa/elfload.c ./linux-user/hppa/elfload.c
index ff4301b2ed..dd5b0b380e 100644
--- ./linux-user/hppa/elfload.c
+++ ./linux-user/hppa/elfload.c
@@ -17,6 +17,13 @@ const char *get_elf_platform(CPUState *cs)
     return "PARISC";
 }
 
+void elf_core_copy_fpregs(target_elf_fpregset_t *r, const CPUArchState *env)
+{
+    for (int i = 0; i < 32; i++) {
+        r->fpr[i] = tswap64(env->fr[i]);
+    }
+}
+
 void elf_core_copy_regs(target_elf_gregset_t *r, const CPUArchState *env)
 {
     int i;
diff --git ./linux-user/hppa/target_elf.h ./linux-user/hppa/target_elf.h
index 22547b1437..4357873aff 100644
--- ./linux-user/hppa/target_elf.h
+++ ./linux-user/hppa/target_elf.h
@@ -39,4 +39,13 @@ typedef struct target_elf_gregset_t {
 #define STACK_ALIGNMENT         64
 #define VDSO_HEADER             "vdso.c.inc"
 
+#define HAVE_ELF_CORE_FPREGS    1
+
+/*
+ * Matches the kernel's elf_fpregset_t (ELF_NFPREG = 32): fr0-fr31.
+ */
+typedef struct target_elf_fpregset_t {
+    uint64_t fpr[32];
+} target_elf_fpregset_t;
+
 #endif
-- 
2.54.0



^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH 4/5] linux-user/riscv: write the floating-point registers to a core dump
  2026-08-05 17:15 [PATCH 1/5] linux-user/alpha: write the floating-point registers to a core dump Matt Turner
  2026-08-05 17:15 ` [PATCH 2/5] linux-user/mips: " Matt Turner
  2026-08-05 17:15 ` [PATCH 3/5] linux-user/hppa: " Matt Turner
@ 2026-08-05 17:15 ` Matt Turner
  2026-08-05 17:15 ` [PATCH 5/5] linux-user/sh4: " Matt Turner
  2026-08-07 16:12 ` [PATCH 1/5] linux-user/alpha: " Helge Deller
  4 siblings, 0 replies; 6+ messages in thread
From: Matt Turner @ 2026-08-05 17:15 UTC (permalink / raw)
  To: qemu-devel; +Cc: Matt Turner, Laurent Vivier, Helge Deller, Pierrick Bouvier

Write an NT_FPREGSET note for RISC-V, matching struct __riscv_d_ext_state
from uapi/asm/ptrace.h: f0-f31 as 64-bit values followed by fcsr.

Signed-off-by: Matt Turner <mattst88@gmail.com>
---
 linux-user/riscv/elfload.c    |  9 +++++++++
 linux-user/riscv/target_elf.h | 11 +++++++++++
 2 files changed, 20 insertions(+)

diff --git ./linux-user/riscv/elfload.c ./linux-user/riscv/elfload.c
index afe103a631..1bc8beacb1 100644
--- ./linux-user/riscv/elfload.c
+++ ./linux-user/riscv/elfload.c
@@ -11,6 +11,15 @@ const char *get_elf_cpu_model(uint32_t eflags)
     return "max";
 }
 
+void elf_core_copy_fpregs(target_elf_fpregset_t *r, const CPURISCVState *env)
+{
+    for (int i = 0; i < 32; i++) {
+        r->fpr[i] = tswap64(env->fpr[i]);
+    }
+    r->fcsr = tswap32(((uint32_t)env->frm << FSR_RD_SHIFT) |
+                      (riscv_cpu_get_fflags((CPURISCVState *)env) << FSR_AEXC_SHIFT));
+}
+
 void elf_core_copy_regs(target_elf_gregset_t *r, const CPURISCVState *env)
 {
     r->pc = tswapal(env->pc);
diff --git ./linux-user/riscv/target_elf.h ./linux-user/riscv/target_elf.h
index 859f726578..185b81a2db 100644
--- ./linux-user/riscv/target_elf.h
+++ ./linux-user/riscv/target_elf.h
@@ -27,4 +27,15 @@ typedef struct target_elf_gregset_t {
     abi_ulong regs[31];
 } target_elf_gregset_t;
 
+#define HAVE_ELF_CORE_FPREGS    1
+
+/*
+ * Matches struct __riscv_d_ext_state from uapi/asm/ptrace.h:
+ *   f0-f31 as 64-bit values followed by fcsr.
+ */
+typedef struct target_elf_fpregset_t {
+    uint64_t fpr[32];
+    uint32_t fcsr;
+} target_elf_fpregset_t;
+
 #endif
-- 
2.54.0



^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH 5/5] linux-user/sh4: write the floating-point registers to a core dump
  2026-08-05 17:15 [PATCH 1/5] linux-user/alpha: write the floating-point registers to a core dump Matt Turner
                   ` (2 preceding siblings ...)
  2026-08-05 17:15 ` [PATCH 4/5] linux-user/riscv: " Matt Turner
@ 2026-08-05 17:15 ` Matt Turner
  2026-08-07 16:12 ` [PATCH 1/5] linux-user/alpha: " Helge Deller
  4 siblings, 0 replies; 6+ messages in thread
From: Matt Turner @ 2026-08-05 17:15 UTC (permalink / raw)
  To: qemu-devel; +Cc: Matt Turner, Laurent Vivier, Helge Deller, Pierrick Bouvier

Write an NT_FPREGSET note for SH4, matching struct user_fpu_struct
from arch/sh/include/asm/user.h: fr0-fr15, xf0-xf15, fpscr, fpul.

Signed-off-by: Matt Turner <mattst88@gmail.com>
---
 linux-user/sh4/elfload.c    | 10 ++++++++++
 linux-user/sh4/target_elf.h | 12 ++++++++++++
 2 files changed, 22 insertions(+)

diff --git ./linux-user/sh4/elfload.c ./linux-user/sh4/elfload.c
index f03ce49e7d..41601626ca 100644
--- ./linux-user/sh4/elfload.c
+++ ./linux-user/sh4/elfload.c
@@ -52,6 +52,16 @@ abi_ulong get_elf_hwcap(CPUState *cs)
     return hwcap;
 }
 
+void elf_core_copy_fpregs(target_elf_fpregset_t *r, const CPUSH4State *env)
+{
+    for (int i = 0; i < 16; i++) {
+        r->fpregs[i] = tswap32(env->fregs[i]);
+        r->xfpregs[i] = tswap32(env->fregs[16 + i]);
+    }
+    r->fpscr = tswap32(env->fpscr);
+    r->fpul = tswap32(env->fpul);
+}
+
 void elf_core_copy_regs(target_elf_gregset_t *r, const CPUSH4State *env)
 {
     for (int i = 0; i < 16; i++) {
diff --git ./linux-user/sh4/target_elf.h ./linux-user/sh4/target_elf.h
index 3fcb63d409..5923022036 100644
--- ./linux-user/sh4/target_elf.h
+++ ./linux-user/sh4/target_elf.h
@@ -25,4 +25,16 @@ typedef struct target_elf_gregset_t {
     struct target_pt_regs pt;
 } target_elf_gregset_t;
 
+#define HAVE_ELF_CORE_FPREGS    1
+
+/*
+ * Matches struct user_fpu_struct from arch/sh/include/asm/user.h.
+ */
+typedef struct target_elf_fpregset_t {
+    uint32_t fpregs[16];
+    uint32_t xfpregs[16];
+    uint32_t fpscr;
+    uint32_t fpul;
+} target_elf_fpregset_t;
+
 #endif
-- 
2.54.0



^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH 1/5] linux-user/alpha: write the floating-point registers to a core dump
  2026-08-05 17:15 [PATCH 1/5] linux-user/alpha: write the floating-point registers to a core dump Matt Turner
                   ` (3 preceding siblings ...)
  2026-08-05 17:15 ` [PATCH 5/5] linux-user/sh4: " Matt Turner
@ 2026-08-07 16:12 ` Helge Deller
  4 siblings, 0 replies; 6+ messages in thread
From: Helge Deller @ 2026-08-07 16:12 UTC (permalink / raw)
  To: Matt Turner, qemu-devel; +Cc: Laurent Vivier, Pierrick Bouvier

On 8/5/26 19:15, Matt Turner wrote:
> A guest core carried only the general-purpose registers, so a debugger
> opening one reported every floating-point register as unavailable --
> including the arguments of the function that crashed.
> 
> Implement HAVE_ELF_CORE_FPREGS for Alpha: define target_elf_fpregset_t
> to match the kernel's layout ($f0-$f30 plus the control register in the
> slot $f31 would occupy) and fill it from elf_core_copy_fpregs().
> 
> Checked with lldb on a core from a program that faults with live values
> in $f16 and $f17: both read back correctly, as does the control register.
> 
> Signed-off-by: Matt Turner <mattst88@gmail.com>
> ---
>   linux-user/alpha/elfload.c    | 10 ++++++++++
>   linux-user/alpha/target_elf.h | 11 +++++++++++
>   2 files changed, 21 insertions(+)
For the whole series:
Reviewed-by: Helge Deller <deller@gmx.de>

series queued up for past qemu-v11.1

Thanks!
Helge


^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2026-08-07 16:13 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-08-05 17:15 [PATCH 1/5] linux-user/alpha: write the floating-point registers to a core dump Matt Turner
2026-08-05 17:15 ` [PATCH 2/5] linux-user/mips: " Matt Turner
2026-08-05 17:15 ` [PATCH 3/5] linux-user/hppa: " Matt Turner
2026-08-05 17:15 ` [PATCH 4/5] linux-user/riscv: " Matt Turner
2026-08-05 17:15 ` [PATCH 5/5] linux-user/sh4: " Matt Turner
2026-08-07 16:12 ` [PATCH 1/5] linux-user/alpha: " Helge Deller

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