Add basic support to run various MIPS variants via kunit_tool using the virtualized malta platform.
Signed-off-by: Thomas Weißschuh thomas.weissschuh@linutronix.de --- Changes in v4: - Rebase on v6.16-rc1 - Pick up reviews from David - Clarify that GIC page is linked to vDSO - Link to v3: https://lore.kernel.org/r/20250415-kunit-mips-v3-0-4ec2461b5a7e@linutronix.d...
Changes in v3: - Also skip VDSO_RANDOMIZE_SIZE adjustment for kthreads - Link to v2: https://lore.kernel.org/r/20250414-kunit-mips-v2-0-4cf01e1a29e6@linutronix.d...
Changes in v2: - Fix usercopy kunit test by handling ABI-less tasks in stack_top() - Drop change to mm initialization. The broken test is not built by default anymore. - Link to v1: https://lore.kernel.org/r/20250212-kunit-mips-v1-0-eb49c9d76615@linutronix.d...
--- Thomas Weißschuh (2): MIPS: Don't crash in stack_top() for tasks without ABI or vDSO kunit: qemu_configs: Add MIPS configurations
arch/mips/kernel/process.c | 16 +++++++++------- tools/testing/kunit/qemu_configs/mips.py | 18 ++++++++++++++++++ tools/testing/kunit/qemu_configs/mips64.py | 19 +++++++++++++++++++ tools/testing/kunit/qemu_configs/mips64el.py | 19 +++++++++++++++++++ tools/testing/kunit/qemu_configs/mipsel.py | 18 ++++++++++++++++++ 5 files changed, 83 insertions(+), 7 deletions(-) --- base-commit: 19272b37aa4f83ca52bdf9c16d5d81bdd1354494 change-id: 20241014-kunit-mips-e4fe1c265ed7
Best regards,
Not all tasks have an ABI associated or vDSO mapped, for example kthreads never do. If such a task ever ends up calling stack_top(), it will derefence the NULL ABI pointer and crash.
This can for example happen when using kunit:
mips_stack_top+0x28/0xc0 arch_pick_mmap_layout+0x190/0x220 kunit_vm_mmap_init+0xf8/0x138 __kunit_add_resource+0x40/0xa8 kunit_vm_mmap+0x88/0xd8 usercopy_test_init+0xb8/0x240 kunit_try_run_case+0x5c/0x1a8 kunit_generic_run_threadfn_adapter+0x28/0x50 kthread+0x118/0x240 ret_from_kernel_thread+0x14/0x1c
Only dereference the ABI point if it is set.
The GIC page is also included as it is specific to the vDSO. Also move the randomization adjustment into the same conditional.
Signed-off-by: Thomas Weißschuh thomas.weissschuh@linutronix.de Reviewed-by: David Gow davidgow@google.com --- arch/mips/kernel/process.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c index b630604c577f9ff3f2493b0f254363e499c8318c..02aa6a04a21da437909eeac4f149155cc298f5b5 100644 --- a/arch/mips/kernel/process.c +++ b/arch/mips/kernel/process.c @@ -690,18 +690,20 @@ unsigned long mips_stack_top(void) }
/* Space for the VDSO, data page & GIC user page */ - top -= PAGE_ALIGN(current->thread.abi->vdso->size); - top -= PAGE_SIZE; - top -= mips_gic_present() ? PAGE_SIZE : 0; + if (current->thread.abi) { + top -= PAGE_ALIGN(current->thread.abi->vdso->size); + top -= PAGE_SIZE; + top -= mips_gic_present() ? PAGE_SIZE : 0; + + /* Space to randomize the VDSO base */ + if (current->flags & PF_RANDOMIZE) + top -= VDSO_RANDOMIZE_SIZE; + }
/* Space for cache colour alignment */ if (cpu_has_dc_aliases) top -= shm_align_mask + 1;
- /* Space to randomize the VDSO base */ - if (current->flags & PF_RANDOMIZE) - top -= VDSO_RANDOMIZE_SIZE; - return top; }
Reviewed-by: Huacai Chen chenhuacai@loongson.cn
On Wed, Jun 11, 2025 at 7:28 PM Thomas Weißschuh thomas.weissschuh@linutronix.de wrote:
Not all tasks have an ABI associated or vDSO mapped, for example kthreads never do. If such a task ever ends up calling stack_top(), it will derefence the NULL ABI pointer and crash.
This can for example happen when using kunit:
mips_stack_top+0x28/0xc0 arch_pick_mmap_layout+0x190/0x220 kunit_vm_mmap_init+0xf8/0x138 __kunit_add_resource+0x40/0xa8 kunit_vm_mmap+0x88/0xd8 usercopy_test_init+0xb8/0x240 kunit_try_run_case+0x5c/0x1a8 kunit_generic_run_threadfn_adapter+0x28/0x50 kthread+0x118/0x240 ret_from_kernel_thread+0x14/0x1cOnly dereference the ABI point if it is set.
The GIC page is also included as it is specific to the vDSO. Also move the randomization adjustment into the same conditional.
Signed-off-by: Thomas Weißschuh thomas.weissschuh@linutronix.de Reviewed-by: David Gow davidgow@google.com
arch/mips/kernel/process.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c index b630604c577f9ff3f2493b0f254363e499c8318c..02aa6a04a21da437909eeac4f149155cc298f5b5 100644 --- a/arch/mips/kernel/process.c +++ b/arch/mips/kernel/process.c @@ -690,18 +690,20 @@ unsigned long mips_stack_top(void) }
/* Space for the VDSO, data page & GIC user page */
top -= PAGE_ALIGN(current->thread.abi->vdso->size);top -= PAGE_SIZE;top -= mips_gic_present() ? PAGE_SIZE : 0;
if (current->thread.abi) {top -= PAGE_ALIGN(current->thread.abi->vdso->size);top -= PAGE_SIZE;top -= mips_gic_present() ? PAGE_SIZE : 0;/* Space to randomize the VDSO base */if (current->flags & PF_RANDOMIZE)top -= VDSO_RANDOMIZE_SIZE;} /* Space for cache colour alignment */ if (cpu_has_dc_aliases) top -= shm_align_mask + 1;
/* Space to randomize the VDSO base */if (current->flags & PF_RANDOMIZE)top -= VDSO_RANDOMIZE_SIZE;return top;}
-- 2.49.0
On Wed, Jun 11, 2025 at 01:28:26PM +0200, Thomas Weißschuh wrote:
Not all tasks have an ABI associated or vDSO mapped, for example kthreads never do. If such a task ever ends up calling stack_top(), it will derefence the NULL ABI pointer and crash.
This can for example happen when using kunit:
mips_stack_top+0x28/0xc0 arch_pick_mmap_layout+0x190/0x220 kunit_vm_mmap_init+0xf8/0x138 __kunit_add_resource+0x40/0xa8 kunit_vm_mmap+0x88/0xd8 usercopy_test_init+0xb8/0x240 kunit_try_run_case+0x5c/0x1a8 kunit_generic_run_threadfn_adapter+0x28/0x50 kthread+0x118/0x240 ret_from_kernel_thread+0x14/0x1cOnly dereference the ABI point if it is set.
The GIC page is also included as it is specific to the vDSO. Also move the randomization adjustment into the same conditional.
Signed-off-by: Thomas Weißschuh thomas.weissschuh@linutronix.de Reviewed-by: David Gow davidgow@google.com
arch/mips/kernel/process.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-)
applied to mips-next.
Thomas.
Add basic support to run various MIPS variants via kunit_tool using the virtualized malta platform.
Signed-off-by: Thomas Weißschuh thomas.weissschuh@linutronix.de Reviewed-by: David Gow davidgow@google.com --- tools/testing/kunit/qemu_configs/mips.py | 18 ++++++++++++++++++ tools/testing/kunit/qemu_configs/mips64.py | 19 +++++++++++++++++++ tools/testing/kunit/qemu_configs/mips64el.py | 19 +++++++++++++++++++ tools/testing/kunit/qemu_configs/mipsel.py | 18 ++++++++++++++++++ 4 files changed, 74 insertions(+)
diff --git a/tools/testing/kunit/qemu_configs/mips.py b/tools/testing/kunit/qemu_configs/mips.py new file mode 100644 index 0000000000000000000000000000000000000000..8899ac157b30bd2ee847eacd5b90fe6ad4e5fb04 --- /dev/null +++ b/tools/testing/kunit/qemu_configs/mips.py @@ -0,0 +1,18 @@ +# SPDX-License-Identifier: GPL-2.0 + +from ..qemu_config import QemuArchParams + +QEMU_ARCH = QemuArchParams(linux_arch='mips', + kconfig=''' +CONFIG_32BIT=y +CONFIG_CPU_BIG_ENDIAN=y +CONFIG_MIPS_MALTA=y +CONFIG_SERIAL_8250=y +CONFIG_SERIAL_8250_CONSOLE=y +CONFIG_POWER_RESET=y +CONFIG_POWER_RESET_SYSCON=y +''', + qemu_arch='mips', + kernel_path='vmlinuz', + kernel_command_line='console=ttyS0', + extra_qemu_params=['-M', 'malta']) diff --git a/tools/testing/kunit/qemu_configs/mips64.py b/tools/testing/kunit/qemu_configs/mips64.py new file mode 100644 index 0000000000000000000000000000000000000000..1478aed05b94da4914f34c6a8affdcfe34eb88ea --- /dev/null +++ b/tools/testing/kunit/qemu_configs/mips64.py @@ -0,0 +1,19 @@ +# SPDX-License-Identifier: GPL-2.0 + +from ..qemu_config import QemuArchParams + +QEMU_ARCH = QemuArchParams(linux_arch='mips', + kconfig=''' +CONFIG_CPU_MIPS64_R2=y +CONFIG_64BIT=y +CONFIG_CPU_BIG_ENDIAN=y +CONFIG_MIPS_MALTA=y +CONFIG_SERIAL_8250=y +CONFIG_SERIAL_8250_CONSOLE=y +CONFIG_POWER_RESET=y +CONFIG_POWER_RESET_SYSCON=y +''', + qemu_arch='mips64', + kernel_path='vmlinuz', + kernel_command_line='console=ttyS0', + extra_qemu_params=['-M', 'malta', '-cpu', '5KEc']) diff --git a/tools/testing/kunit/qemu_configs/mips64el.py b/tools/testing/kunit/qemu_configs/mips64el.py new file mode 100644 index 0000000000000000000000000000000000000000..300c711d7a82500b2ebcb4cf1467b6f72b5c17aa --- /dev/null +++ b/tools/testing/kunit/qemu_configs/mips64el.py @@ -0,0 +1,19 @@ +# SPDX-License-Identifier: GPL-2.0 + +from ..qemu_config import QemuArchParams + +QEMU_ARCH = QemuArchParams(linux_arch='mips', + kconfig=''' +CONFIG_CPU_MIPS64_R2=y +CONFIG_64BIT=y +CONFIG_CPU_LITTLE_ENDIAN=y +CONFIG_MIPS_MALTA=y +CONFIG_SERIAL_8250=y +CONFIG_SERIAL_8250_CONSOLE=y +CONFIG_POWER_RESET=y +CONFIG_POWER_RESET_SYSCON=y +''', + qemu_arch='mips64el', + kernel_path='vmlinuz', + kernel_command_line='console=ttyS0', + extra_qemu_params=['-M', 'malta', '-cpu', '5KEc']) diff --git a/tools/testing/kunit/qemu_configs/mipsel.py b/tools/testing/kunit/qemu_configs/mipsel.py new file mode 100644 index 0000000000000000000000000000000000000000..3d3543315b45776d0e77fb5c00c8c0a89eafdffd --- /dev/null +++ b/tools/testing/kunit/qemu_configs/mipsel.py @@ -0,0 +1,18 @@ +# SPDX-License-Identifier: GPL-2.0 + +from ..qemu_config import QemuArchParams + +QEMU_ARCH = QemuArchParams(linux_arch='mips', + kconfig=''' +CONFIG_32BIT=y +CONFIG_CPU_LITTLE_ENDIAN=y +CONFIG_MIPS_MALTA=y +CONFIG_SERIAL_8250=y +CONFIG_SERIAL_8250_CONSOLE=y +CONFIG_POWER_RESET=y +CONFIG_POWER_RESET_SYSCON=y +''', + qemu_arch='mipsel', + kernel_path='vmlinuz', + kernel_command_line='console=ttyS0', + extra_qemu_params=['-M', 'malta'])
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Thomas Weißschuh