From: "Mike Rapoport (IBM)" <rppt@xxxxxxxxxx>
Dynamic ftrace must allocate memory for code and this was impossible
without CONFIG_MODULES.
With jitalloc separated from the modules code, the jit_text_alloc() is
available regardless of CONFIG_MODULE.
Move jitalloc initialization to x86/mm/init.c so that it won't get
compiled away when CONFIG_MODULE=n and enable dynamic ftrace
unconditionally.
Signed-off-by: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
---
arch/x86/Kconfig | 1 +
arch/x86/kernel/ftrace.c | 9 --------
arch/x86/kernel/module.c | 44 --------------------------------------
arch/x86/mm/init.c | 46 ++++++++++++++++++++++++++++++++++++++++
4 files changed, 47 insertions(+), 53 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 53bab123a8ee..fac4add6ce16 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -35,6 +35,7 @@ config X86_64
select SWIOTLB
select ARCH_HAS_ELFCORE_COMPAT
select ZONE_DMA32
+ select JIT_ALLOC if DYNAMIC_FTRACE
config FORCE_DYNAMIC_FTRACE
def_bool y
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 157c8a799704..aa99536b824c 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -261,7 +261,6 @@ void arch_ftrace_update_code(int command)
/* Currently only x86_64 supports dynamic trampolines */
#ifdef CONFIG_X86_64
-#ifdef CONFIG_MODULES
/* Module allocation simplifies allocating memory for code */
static inline void *alloc_tramp(unsigned long size)
{
@@ -271,14 +270,6 @@ static inline void tramp_free(void *tramp)
{
jit_free(tramp);
}
-#else
-/* Trampolines can only be created if modules are supported */
-static inline void *alloc_tramp(unsigned long size)
-{
- return NULL;
-}
-static inline void tramp_free(void *tramp) { }
-#endif
/* Defined as markers to the end of the ftrace default trampolines */
extern void ftrace_regs_caller_end(void);
diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
index cacca613b8bd..94a00dc103cd 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -19,7 +19,6 @@
#include <linux/jump_label.h>
#include <linux/random.h>
#include <linux/memory.h>
-#include <linux/jitalloc.h>
#include <asm/text-patching.h>
#include <asm/page.h>
@@ -37,49 +36,6 @@ do { \
} while (0)
#endif
-#ifdef CONFIG_RANDOMIZE_BASE
-static unsigned long module_load_offset;
-
-/* Mutex protects the module_load_offset. */
-static DEFINE_MUTEX(module_kaslr_mutex);
-
-static unsigned long int get_module_load_offset(void)
-{
- if (kaslr_enabled()) {
- mutex_lock(&module_kaslr_mutex);
- /*
- * Calculate the module_load_offset the first time this
- * code is called. Once calculated it stays the same until
- * reboot.
- */
- if (module_load_offset == 0)
- module_load_offset =
- get_random_u32_inclusive(1, 1024) * PAGE_SIZE;
- mutex_unlock(&module_kaslr_mutex);
- }
- return module_load_offset;
-}
-#else
-static unsigned long int get_module_load_offset(void)
-{
- return 0;
-}
-#endif
-
-static struct jit_alloc_params jit_alloc_params = {
- .alignment = JIT_ALLOC_ALIGN,
- .flags = JIT_ALLOC_KASAN_SHADOW,
-};
-
-struct jit_alloc_params *jit_alloc_arch_params(void)
-{
- jit_alloc_params.text.pgprot = PAGE_KERNEL;
- jit_alloc_params.text.start = MODULES_VADDR + get_module_load_offset();
- jit_alloc_params.text.end = MODULES_END;
-
- return &jit_alloc_params;
-}
-
#ifdef CONFIG_X86_32
int apply_relocate(Elf32_Shdr *sechdrs,
const char *strtab,
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 3cdac0f0055d..ffaf9a3840ce 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -7,6 +7,7 @@
#include <linux/swapops.h>
#include <linux/kmemleak.h>
#include <linux/sched/task.h>
+#include <linux/jitalloc.h>
#include <asm/set_memory.h>
#include <asm/e820/api.h>
@@ -1084,3 +1085,48 @@ unsigned long arch_max_swapfile_size(void)
return pages;
}
#endif
+
+#ifdef CONFIG_JIT_ALLOC
+#ifdef CONFIG_RANDOMIZE_BASE
+static unsigned long jit_load_offset;
+
+/* Mutex protects the jit_load_offset. */
+static DEFINE_MUTEX(jit_kaslr_mutex);
+
+static unsigned long int get_jit_load_offset(void)
+{
+ if (kaslr_enabled()) {
+ mutex_lock(&jit_kaslr_mutex);
+ /*
+ * Calculate the jit_load_offset the first time this
+ * code is called. Once calculated it stays the same until
+ * reboot.
+ */
+ if (jit_load_offset == 0)
+ jit_load_offset =
+ get_random_u32_inclusive(1, 1024) * PAGE_SIZE;
+ mutex_unlock(&jit_kaslr_mutex);
+ }
+ return jit_load_offset;
+}
+#else
+static unsigned long int get_jit_load_offset(void)
+{
+ return 0;
+}
+#endif
+
+static struct jit_alloc_params jit_alloc_params = {
+ .alignment = JIT_ALLOC_ALIGN,
+ .flags = JIT_ALLOC_KASAN_SHADOW,
+};
+
+struct jit_alloc_params *jit_alloc_arch_params(void)
+{
+ jit_alloc_params.text.pgprot = PAGE_KERNEL;
+ jit_alloc_params.text.start = MODULES_VADDR + get_jit_load_offset();
+ jit_alloc_params.text.end = MODULES_END;
+
+ return &jit_alloc_params;
+}
+#endif /* CONFIG_JIT_ALLOC */
--
2.35.1
