From: Jarkko Sakkinen <jarkko@kernel.org>
To: linux-riscv@lists.infradead.org
Cc: Jarkko Sakkinen <jarkko@kernel.org>,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
linux-kernel@vger.kernel.org,
Luis Chamberlain <mcgrof@kernel.org>,
linux-modules@vger.kernel.org,
"Naveen N . Rao" <naveen.n.rao@linux.ibm.com>,
Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
"David S . Miller" <davem@davemloft.net>,
Masami Hiramatsu <mhiramat@kernel.org>
Subject: [PATCH v6 2/2] arch/riscv: Enable kprobes when CONFIG_MODULES=n
Date: Tue, 26 Mar 2024 03:21:02 +0200 [thread overview]
Message-ID: <20240326012102.27438-2-jarkko@kernel.org> (raw)
In-Reply-To: <20240326012102.27438-1-jarkko@kernel.org>
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>
---
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
+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);
+}
--
2.44.0
prev parent reply other threads:[~2024-03-26 1:21 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-26 1:21 [PATCH v6 1/2] kprobes: implemente trampoline memory allocator Jarkko Sakkinen
2024-03-26 1:21 ` Jarkko Sakkinen [this message]
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