[PULL 0/5] Linux user next patches

[PULL 0/5] Linux user next patches

[Helge Deller]

From: Helge Deller <deller@gmx.de>

The following changes since commit d7a65d1793d691d356a56833620f7d1e6f5d653b:

  Merge tag 'hppa-a400-updates-pull-request' of https://github.com/hdeller/qemu-hppa into staging (2026-10-03 14:17:49 +0200)

are available in the Git repository at:

  https://github.com/hdeller/qemu-hppa.git tags/linux-user-next-pull-request

for you to fetch changes up to 8e021b85cc06caec24a24302aa68f040a0970c12:

  linux-user/mips: pick Loongson-3A4000 if a pre-r6 mips64 binary needs nan2008 (2026-10-04 13:32:14 +0200)

----------------------------------------------------------------
linux user patches

Some patches for linux-user, which
- make it possible to run pre-r6 mips64 binaries that need nan2008 without
  requiring the user to explicitly set a compatible -cpu, and
- copy the executable's e_flags into core dumps on mips and riscv

----------------------------------------------------------------

Alex Rønne Petersen (2):
  target/mips: fix Loongson-3A4000 definition to have abs2008 and
    nan2008
  linux-user/mips: pick Loongson-3A4000 if a pre-r6 mips64 binary needs
    nan2008

Matt Turner (3):
  linux-user: add elf_core_eflags() hook for core dump e_flags
  linux-user/mips64: set EF_MIPS_ABI2 in mipsn32 core dumps
  linux-user/riscv: copy the executable's e_flags into core dumps

 linux-user/elfload.c           |  7 ++++++-
 linux-user/mips/elfload.c      | 14 ++++++++------
 linux-user/mips64/target_elf.h |  2 ++
 linux-user/riscv/target_elf.h  |  3 +++
 target/mips/cpu-defs.c.inc     |  4 ++--
 5 files changed, 21 insertions(+), 9 deletions(-)

-- 
2.54.0

[PULL 1/5] linux-user: add elf_core_eflags() hook for core dump e_flags

[Helge Deller]

From: Matt Turner <mattst88@gmail.com>

Let targets set e_flags in the core file header. Default to 0, as
before.

Signed-off-by: Helge Deller <deller@gmx.de>
---
 linux-user/elfload.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index c4bdaa146a..c188fa03c3 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -144,6 +144,10 @@ typedef abi_int         target_pid_t;
 #define EXSTACK_DEFAULT false
 #endif
 
+#ifndef elf_core_eflags
+#define elf_core_eflags(info) 0
+#endif
+
 /*
  * Provide fallback definitions that the target may omit.
  * One way or another, we'll get a link error if the setting of
@@ -2212,7 +2216,8 @@ static int elf_core_dump(int signr, const CPUArchState *env)
 
         /* Create elf file header. */
         hptr = header;
-        fill_elf_header(hptr, css.count + 1, ELF_MACHINE, 0);
+        fill_elf_header(hptr, css.count + 1, ELF_MACHINE,
+                        elf_core_eflags(ts->info));
         hptr += sizeof(struct elfhdr);
 
         /* Create elf program headers. */
-- 
2.54.0

[PULL 2/5] linux-user/mips64: set EF_MIPS_ABI2 in mipsn32 core dumps

[Helge Deller]

From: Matt Turner <mattst88@gmail.com>

mipsn32 core files had e_flags 0, so gdb took them for o32, found no
general-purpose registers and failed with an internal error in
frame_unwind_find_by_frame.

Linux sets e_flags to EF_MIPS_ABI2 for n32 cores (user_mipsn32_view in
arch/mips/kernel/ptrace.c).

Signed-off-by: Helge Deller <deller@gmx.de>
---
 linux-user/mips64/target_elf.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/linux-user/mips64/target_elf.h b/linux-user/mips64/target_elf.h
index efb5d97563..fd9fb89269 100644
--- a/linux-user/mips64/target_elf.h
+++ b/linux-user/mips64/target_elf.h
@@ -16,6 +16,8 @@
 
 #ifdef TARGET_ABI_MIPSN32
 #define elf_check_abi(x)        ((x) & EF_MIPS_ABI2)
+/* See linux kernel: arch/mips/kernel/ptrace.c, user_mipsn32_view.  */
+#define elf_core_eflags(info)   EF_MIPS_ABI2
 #else
 #define elf_check_abi(x)        (!((x) & EF_MIPS_ABI2))
 #endif
-- 
2.54.0

[PULL 3/5] linux-user/riscv: copy the executable's e_flags into core dumps

[Helge Deller]

From: Matt Turner <mattst88@gmail.com>

Since commit 8c94db0ae97c ("binfmt_elf: preserve original ELF e_flags
for core dumps"), Linux writes the main executable's e_flags into RISC-V
core files, so debuggers can see the float ABI and RVC. QEMU wrote 0.

Signed-off-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
---
 linux-user/riscv/target_elf.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/linux-user/riscv/target_elf.h b/linux-user/riscv/target_elf.h
index 185b81a2db..e99a9d92ca 100644
--- a/linux-user/riscv/target_elf.h
+++ b/linux-user/riscv/target_elf.h
@@ -21,6 +21,9 @@
 #define HAVE_ELF_HWCAP          1
 #define HAVE_ELF_CORE_DUMP      1
 
+/* See linux kernel: ARCH_HAS_ELF_CORE_EFLAGS.  */
+#define elf_core_eflags(info)   ((info)->elf_flags)
+
 /* Mirrors struct user_regs_struct: pc followed by x1 (ra) .. x31 (t6). */
 typedef struct target_elf_gregset_t {
     abi_ulong pc;
-- 
2.54.0

[PULL 4/5] target/mips: fix Loongson-3A4000 definition to have abs2008 and nan2008

[Helge Deller]

From: Alex Rønne Petersen <alex@alexrp.com>

Checked on a Loongson 3B4000; this uarch operates in 2008 mode.

Signed-off-by: Alex Rønne Petersen <alex@alexrp.com>
Signed-off-by: Helge Deller <deller@gmx.de>
---
 target/mips/cpu-defs.c.inc | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/target/mips/cpu-defs.c.inc b/target/mips/cpu-defs.c.inc
index cc1916232f..b2ddfa1e82 100644
--- a/target/mips/cpu-defs.c.inc
+++ b/target/mips/cpu-defs.c.inc
@@ -941,8 +941,8 @@ const mips_def_t mips_defs[] =
                     (1 << CP0PG_ELPA) | (1 << CP0PG_IEC),
         .CP1_fcr0 = (0x5 << FCR0_PRID) | (0x1 << FCR0_REV) | (0x1 << FCR0_F64) |
                     (0x1 << FCR0_PS) | (0x1 << FCR0_L) | (0x1 << FCR0_W) |
-                    (0x1 << FCR0_D) | (0x1 << FCR0_S),
-        .CP1_fcr31 = 0,
+                    (0x1 << FCR0_D) | (0x1 << FCR0_S) | (0x1 << FCR0_HAS2008),
+        .CP1_fcr31 = (1 << FCR31_ABS2008) | (1 << FCR31_NAN2008),
         .CP1_fcr31_rw_bitmask = 0xFF83FFFF,
         .MSAIR = (0x01 << MSAIR_ProcID) | (0x40 << MSAIR_Rev),
         .lcsr_cpucfg1 = (1 << CPUCFG1_FP) | (2 << CPUCFG1_FPREV) |
-- 
2.54.0

[PULL 5/5] linux-user/mips: pick Loongson-3A4000 if a pre-r6 mips64 binary needs nan2008

[Helge Deller]

From: Alex Rønne Petersen <alex@alexrp.com>

Before this patch, we'd pick MIPS64R2-generic which does not have 2008 mode, so
the binary would just fail to run without an explicit -cpu flag. Now it'll just
work as in the pre-r6 mips32 case.

Signed-off-by: Alex Rønne Petersen <alex@alexrp.com>
Signed-off-by: Helge Deller <deller@gmx.de>
---
 linux-user/mips/elfload.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/linux-user/mips/elfload.c b/linux-user/mips/elfload.c
index 1d62ae0a4d..19850f4835 100644
--- a/linux-user/mips/elfload.c
+++ b/linux-user/mips/elfload.c
@@ -20,17 +20,19 @@ const char *get_elf_cpu_model(uint32_t eflags)
     case EF_MIPS_MACH_LS2F:
         return "Loongson-2F";
     case EF_MIPS_MACH_LS3A:
-        return "Loongson-3A1000";
+        return (eflags & EF_MIPS_NAN2008) ? "Loongson-3A4000"
+                                          : "Loongson-3A1000";
     default:
         break;
     }
-    switch (eflags & EF_MIPS_ARCH) {
-    case EF_MIPS_ARCH_64R6:
+    if ((eflags & EF_MIPS_ARCH) == EF_MIPS_ARCH_64R6) {
         return "I6400";
-    case EF_MIPS_ARCH_64R2:
+    }
+    if (eflags & EF_MIPS_NAN2008) {
+        return "Loongson-3A4000";
+    }
+    if ((eflags & EF_MIPS_ARCH) == EF_MIPS_ARCH_64R2) {
         return "MIPS64R2-generic";
-    default:
-        break;
     }
     return "5KEf";
 #else
-- 
2.54.0

Re: [PULL 0/5] Linux user next patches

[Richard Henderson]

On 10/4/26 13:43, Helge Deller wrote:
> From: Helge Deller<deller@gmx.de>
> 
> The following changes since commit d7a65d1793d691d356a56833620f7d1e6f5d653b:
> 
>    Merge tag 'hppa-a400-updates-pull-request' ofhttps://github.com/hdeller/qemu-hppa into staging (2026-10-03 14:17:49 +0200)
> 
> are available in the Git repository at:
> 
>    https://github.com/hdeller/qemu-hppa.git tags/linux-user-next-pull-request
> 
> for you to fetch changes up to 8e021b85cc06caec24a24302aa68f040a0970c12:
> 
>    linux-user/mips: pick Loongson-3A4000 if a pre-r6 mips64 binary needs nan2008 (2026-10-04 13:32:14 +0200)
> 
> ----------------------------------------------------------------
> linux user patches
> 
> Some patches for linux-user, which
> - make it possible to run pre-r6 mips64 binaries that need nan2008 without
>    requiring the user to explicitly set a compatible -cpu, and
> - copy the executable's e_flags into core dumps on mips and riscv

Applied, thanks.

r~