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authorMark Rutland <mark.rutland@arm.com>2019-10-16 18:17:11 +0100
committerMark Rutland <mark.rutland@arm.com>2019-11-06 14:17:30 +0000
commita1326b17ac03a9012cb3d01e434aacb4d67a416c (patch)
tree72dea3e957bfb1651b111e1a613e4f0c9c50733d /arch
parentfbf6c73c5b264c25484fa9f449b5546569fe11f0 (diff)
downloadlinux-a1326b17ac03a9012cb3d01e434aacb4d67a416c.tar.bz2
module/ftrace: handle patchable-function-entry
When using patchable-function-entry, the compiler will record the callsites into a section named "__patchable_function_entries" rather than "__mcount_loc". Let's abstract this difference behind a new FTRACE_CALLSITE_SECTION, so that architectures don't have to handle this explicitly (e.g. with custom module linker scripts). As parisc currently handles this explicitly, it is fixed up accordingly, with its custom linker script removed. Since FTRACE_CALLSITE_SECTION is only defined when DYNAMIC_FTRACE is selected, the parisc module loading code is updated to only use the definition in that case. When DYNAMIC_FTRACE is not selected, modules shouldn't have this section, so this removes some redundant work in that case. To make sure that this is keep up-to-date for modules and the main kernel, a comment is added to vmlinux.lds.h, with the existing ifdeffery simplified for legibility. I built parisc generic-{32,64}bit_defconfig with DYNAMIC_FTRACE enabled, and verified that the section made it into the .ko files for modules. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Helge Deller <deller@gmx.de> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Torsten Duwe <duwe@suse.de> Tested-by: Amit Daniel Kachhap <amit.kachhap@arm.com> Tested-by: Sven Schnelle <svens@stackframe.org> Tested-by: Torsten Duwe <duwe@suse.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com> Cc: Jessica Yu <jeyu@kernel.org> Cc: linux-parisc@vger.kernel.org
Diffstat (limited to 'arch')
-rw-r--r--arch/parisc/Makefile1
-rw-r--r--arch/parisc/kernel/module.c10
-rw-r--r--arch/parisc/kernel/module.lds7
3 files changed, 7 insertions, 11 deletions
diff --git a/arch/parisc/Makefile b/arch/parisc/Makefile
index 36b834f1c933..dca8f2de8cf5 100644
--- a/arch/parisc/Makefile
+++ b/arch/parisc/Makefile
@@ -60,7 +60,6 @@ KBUILD_CFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY=1 \
-DFTRACE_PATCHABLE_FUNCTION_SIZE=$(NOP_COUNT)
CC_FLAGS_FTRACE := -fpatchable-function-entry=$(NOP_COUNT),$(shell echo $$(($(NOP_COUNT)-1)))
-KBUILD_LDS_MODULE += $(srctree)/arch/parisc/kernel/module.lds
endif
OBJCOPY_FLAGS =-O binary -R .note -R .comment -S
diff --git a/arch/parisc/kernel/module.c b/arch/parisc/kernel/module.c
index ac5f34993b53..1c50093e2ebe 100644
--- a/arch/parisc/kernel/module.c
+++ b/arch/parisc/kernel/module.c
@@ -43,6 +43,7 @@
#include <linux/elf.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
+#include <linux/ftrace.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/bug.h>
@@ -862,7 +863,7 @@ int module_finalize(const Elf_Ehdr *hdr,
const char *strtab = NULL;
const Elf_Shdr *s;
char *secstrings;
- int err, symindex = -1;
+ int symindex = -1;
Elf_Sym *newptr, *oldptr;
Elf_Shdr *symhdr = NULL;
#ifdef DEBUG
@@ -946,11 +947,13 @@ int module_finalize(const Elf_Ehdr *hdr,
/* patch .altinstructions */
apply_alternatives(aseg, aseg + s->sh_size, me->name);
+#ifdef CONFIG_DYNAMIC_FTRACE
/* For 32 bit kernels we're compiling modules with
* -ffunction-sections so we must relocate the addresses in the
- *__mcount_loc section.
+ * ftrace callsite section.
*/
- if (symindex != -1 && !strcmp(secname, "__mcount_loc")) {
+ if (symindex != -1 && !strcmp(secname, FTRACE_CALLSITE_SECTION)) {
+ int err;
if (s->sh_type == SHT_REL)
err = apply_relocate((Elf_Shdr *)sechdrs,
strtab, symindex,
@@ -962,6 +965,7 @@ int module_finalize(const Elf_Ehdr *hdr,
if (err)
return err;
}
+#endif
}
return 0;
}
diff --git a/arch/parisc/kernel/module.lds b/arch/parisc/kernel/module.lds
deleted file mode 100644
index 1a9a92aca5c8..000000000000
--- a/arch/parisc/kernel/module.lds
+++ /dev/null
@@ -1,7 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-
-SECTIONS {
- __mcount_loc : {
- *(__patchable_function_entries)
- }
-}