| Message ID | 20240326134616.7691-2-jarkko@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v7,1/2] kprobes: Implement trampoline memory allocator for tracing | expand |
On Tue, Mar 26, 2024 at 03:46:16PM +0200, Jarkko Sakkinen wrote: > Tacing with kprobes while running a monolithic kernel is currently > impossible due the kernel module allocator dependency. > > Address the issue by implementing textmem API for RISC-V. This doesn't compile for nommu: /build/tmp.3xucsBhqDV/arch/riscv/kernel/execmem.c:10:46: error: 'MODULES_VADDR' undeclared (first use in this function) /build/tmp.3xucsBhqDV/arch/riscv/kernel/execmem.c:11:37: error: 'MODULES_END' undeclared (first use in this function) /build/tmp.3xucsBhqDV/arch/riscv/kernel/execmem.c:14:1: error: control reaches end of non-void function [-Werror=return-type] Clang builds also report: ../arch/riscv/kernel/execmem.c:8:56: warning: omitting the parameter name in a function definition is a C2x extension [-Wc2x-extensions] > > Link: https://www.sochub.fi # for power on testing new SoC's with a minimal stack > Link: https://lore.kernel.org/all/20220608000014.3054333-1-jarkko@profian.com/ # continuation > Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> > --- > v5-v7: > - No changes. > v4: > - Include linux/execmem.h. > v3: > - Architecture independent parts have been split to separate patches. > - Do not change arch/riscv/kernel/module.c as it is out of scope for > this patch set now. Meta comment. I dunno when v1 was sent, but versions can you please relax with submitting new versions of your patches? There's conversations ongoing on v5 at the moment, while this is a more recent version. v2 seems to have been sent on the 23rd and there's been 5 versions in the last day: https://patchwork.kernel.org/project/linux-riscv/list/?submitter=195059&state=* Could you please also try and use a cover letter for patchsets, ideally with a consistent subject? Otherwise I have to manually mark stuff as superseded. Thanks, Conor. > v2: > - Better late than never right? :-) > - Focus only to RISC-V for now to make the patch more digestable. This > is the arch where I use the patch on a daily basis to help with QA. > - Introduce HAVE_KPROBES_ALLOC flag to help with more gradual migration.
On Tue Mar 26, 2024 at 8:42 PM EET, Conor Dooley wrote: > On Tue, Mar 26, 2024 at 03:46:16PM +0200, Jarkko Sakkinen wrote: > > Tacing with kprobes while running a monolithic kernel is currently > > impossible due the kernel module allocator dependency. > > > > Address the issue by implementing textmem API for RISC-V. > > This doesn't compile for nommu: > /build/tmp.3xucsBhqDV/arch/riscv/kernel/execmem.c:10:46: error: 'MODULES_VADDR' undeclared (first use in this function) > /build/tmp.3xucsBhqDV/arch/riscv/kernel/execmem.c:11:37: error: 'MODULES_END' undeclared (first use in this function) > /build/tmp.3xucsBhqDV/arch/riscv/kernel/execmem.c:14:1: error: control reaches end of non-void function [-Werror=return-type] > Clang builds also report: > ../arch/riscv/kernel/execmem.c:8:56: warning: omitting the parameter name in a function definition is a C2x extension [-Wc2x-extensions] > > > > > Link: https://www.sochub.fi # for power on testing new SoC's with a minimal stack > > Link: https://lore.kernel.org/all/20220608000014.3054333-1-jarkko@profian.com/ # continuation > > Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> > > --- > > v5-v7: > > - No changes. > > v4: > > - Include linux/execmem.h. > > v3: > > - Architecture independent parts have been split to separate patches. > > - Do not change arch/riscv/kernel/module.c as it is out of scope for > > this patch set now. > > Meta comment. I dunno when v1 was sent, but versions can you please > relax with submitting new versions of your patches? There's conversations > ongoing on v5 at the moment, while this is a more recent version. v2 > seems to have been sent on the 23rd and there's been 5 versions in the > last day: > https://patchwork.kernel.org/project/linux-riscv/list/?submitter=195059&state=* > > Could you please also try and use a cover letter for patchsets, ideally > with a consistent subject? Otherwise I have to manually mark stuff as > superseded. Point taken but the work has been taken over by Mark and relevant changes are now sucked into that patch set. > Thanks, > Conor. BR, Jarkko
Le 26/03/2024 à 14:46, Jarkko Sakkinen a écrit : > Tacing with kprobes while running a monolithic kernel is currently > impossible due the kernel module allocator dependency. > > Address the issue by implementing textmem API for RISC-V. > > Link: https://www.sochub.fi # for power on testing new SoC's with a minimal stack > Link: https://lore.kernel.org/all/20220608000014.3054333-1-jarkko@profian.com/ # continuation > Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> > --- > v5-v7: > - No changes. > v4: > - Include linux/execmem.h. > v3: > - Architecture independent parts have been split to separate patches. > - Do not change arch/riscv/kernel/module.c as it is out of scope for > this patch set now. > v2: > - Better late than never right? :-) > - Focus only to RISC-V for now to make the patch more digestable. This > is the arch where I use the patch on a daily basis to help with QA. > - Introduce HAVE_KPROBES_ALLOC flag to help with more gradual migration. > --- > arch/riscv/Kconfig | 1 + > arch/riscv/kernel/Makefile | 3 +++ > arch/riscv/kernel/execmem.c | 22 ++++++++++++++++++++++ > 3 files changed, 26 insertions(+) > create mode 100644 arch/riscv/kernel/execmem.c > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > index e3142ce531a0..499512fb17ff 100644 > --- a/arch/riscv/Kconfig > +++ b/arch/riscv/Kconfig > @@ -132,6 +132,7 @@ config RISCV > select HAVE_KPROBES if !XIP_KERNEL > select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL > select HAVE_KRETPROBES if !XIP_KERNEL > + select HAVE_ALLOC_EXECMEM if !XIP_KERNEL > # https://github.com/ClangBuiltLinux/linux/issues/1881 > select HAVE_LD_DEAD_CODE_DATA_ELIMINATION if !LD_IS_LLD > select HAVE_MOVE_PMD > diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile > index 604d6bf7e476..337797f10d3e 100644 > --- a/arch/riscv/kernel/Makefile > +++ b/arch/riscv/kernel/Makefile > @@ -73,6 +73,9 @@ obj-$(CONFIG_SMP) += cpu_ops.o > > obj-$(CONFIG_RISCV_BOOT_SPINWAIT) += cpu_ops_spinwait.o > obj-$(CONFIG_MODULES) += module.o > +ifeq ($(CONFIG_ALLOC_EXECMEM),y) > +obj-y += execmem.o Why not just : obj-$(CONFIG_ALLOC_EXECMEM) += execmem.o > +endif > obj-$(CONFIG_MODULE_SECTIONS) += module-sections.o > > obj-$(CONFIG_CPU_PM) += suspend_entry.o suspend.o > diff --git a/arch/riscv/kernel/execmem.c b/arch/riscv/kernel/execmem.c > new file mode 100644 > index 000000000000..3e52522ead32 > --- /dev/null > +++ b/arch/riscv/kernel/execmem.c > @@ -0,0 +1,22 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > + > +#include <linux/mm.h> > +#include <linux/execmem.h> > +#include <linux/vmalloc.h> > +#include <asm/sections.h> > + > +void *alloc_execmem(unsigned long size, gfp_t /* gfp */) > +{ > + return __vmalloc_node_range(size, 1, MODULES_VADDR, > + MODULES_END, GFP_KERNEL, Why not use gfp argument ? > + PAGE_KERNEL, 0, NUMA_NO_NODE, > + __builtin_return_address(0)); > +} > + > +void free_execmem(void *region) > +{ > + if (in_interrupt()) > + pr_warn("In interrupt context: vmalloc may not work.\n"); Do you expect that to happen ? module_memfree() has a WARN_ON() meaning this should never happen and if it really does it is not just a poor dmesg warning. > + > + vfree(region); > +}
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index e3142ce531a0..499512fb17ff 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -132,6 +132,7 @@ config RISCV select HAVE_KPROBES if !XIP_KERNEL select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL select HAVE_KRETPROBES if !XIP_KERNEL + select HAVE_ALLOC_EXECMEM if !XIP_KERNEL # https://github.com/ClangBuiltLinux/linux/issues/1881 select HAVE_LD_DEAD_CODE_DATA_ELIMINATION if !LD_IS_LLD select HAVE_MOVE_PMD diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile index 604d6bf7e476..337797f10d3e 100644 --- a/arch/riscv/kernel/Makefile +++ b/arch/riscv/kernel/Makefile @@ -73,6 +73,9 @@ obj-$(CONFIG_SMP) += cpu_ops.o obj-$(CONFIG_RISCV_BOOT_SPINWAIT) += cpu_ops_spinwait.o obj-$(CONFIG_MODULES) += module.o +ifeq ($(CONFIG_ALLOC_EXECMEM),y) +obj-y += execmem.o +endif obj-$(CONFIG_MODULE_SECTIONS) += module-sections.o obj-$(CONFIG_CPU_PM) += suspend_entry.o suspend.o diff --git a/arch/riscv/kernel/execmem.c b/arch/riscv/kernel/execmem.c new file mode 100644 index 000000000000..3e52522ead32 --- /dev/null +++ b/arch/riscv/kernel/execmem.c @@ -0,0 +1,22 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +#include <linux/mm.h> +#include <linux/execmem.h> +#include <linux/vmalloc.h> +#include <asm/sections.h> + +void *alloc_execmem(unsigned long size, gfp_t /* gfp */) +{ + return __vmalloc_node_range(size, 1, MODULES_VADDR, + MODULES_END, GFP_KERNEL, + PAGE_KERNEL, 0, NUMA_NO_NODE, + __builtin_return_address(0)); +} + +void free_execmem(void *region) +{ + if (in_interrupt()) + pr_warn("In interrupt context: vmalloc may not work.\n"); + + vfree(region); +}
Tacing with kprobes while running a monolithic kernel is currently impossible due the kernel module allocator dependency. Address the issue by implementing textmem API for RISC-V. Link: https://www.sochub.fi # for power on testing new SoC's with a minimal stack Link: https://lore.kernel.org/all/20220608000014.3054333-1-jarkko@profian.com/ # continuation Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> --- v5-v7: - No changes. v4: - Include linux/execmem.h. v3: - Architecture independent parts have been split to separate patches. - Do not change arch/riscv/kernel/module.c as it is out of scope for this patch set now. v2: - Better late than never right? :-) - Focus only to RISC-V for now to make the patch more digestable. This is the arch where I use the patch on a daily basis to help with QA. - Introduce HAVE_KPROBES_ALLOC flag to help with more gradual migration. --- arch/riscv/Kconfig | 1 + arch/riscv/kernel/Makefile | 3 +++ arch/riscv/kernel/execmem.c | 22 ++++++++++++++++++++++ 3 files changed, 26 insertions(+) create mode 100644 arch/riscv/kernel/execmem.c