Commit 74aaaa1e authored by Russell King (Oracle)'s avatar Russell King (Oracle)
Browse files

Merge tag 'arm-ftrace-for-rmk' of... 

Merge tag 'arm-ftrace-for-rmk' of git://git.kernel.org/pub/scm/linux/kernel/git/ardb/linux into devel-stable

ARM: ftrace fixes and cleanups

Make all flavors of ftrace available on all builds, regardless of ISA
choice, unwinder choice or compiler:
- use ADD not POP where possible
- fix a couple of Thumb2 related issues
- enable HAVE_FUNCTION_GRAPH_FP_TEST for robustness
- enable the graph tracer with the EABI unwinder
- avoid clobbering frame pointer registers to make Clang happy

Link: https://lore.kernel.org/linux-arm-kernel/20220203082204.1176734-1-ardb@kernel.org/
parents 2fa39482 d6800ca7

arch/arm/Kconfig

+2 −2
Original line number Diff line number Diff line
@@ -91,8 +91,8 @@ config ARM 
	select HAVE_EXIT_THREAD

	select HAVE_FAST_GUP if ARM_LPAE

	select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL

	select HAVE_FUNCTION_GRAPH_TRACER if !THUMB2_KERNEL && !CC_IS_CLANG

	select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !(THUMB2_KERNEL && CC_IS_CLANG)

	select HAVE_FUNCTION_GRAPH_TRACER

	select HAVE_FUNCTION_TRACER if !XIP_KERNEL

	select HAVE_FUTEX_CMPXCHG if FUTEX

	select HAVE_GCC_PLUGINS

	select HAVE_HW_BREAKPOINT if PERF_EVENTS && (CPU_V6 || CPU_V6K || CPU_V7)

arch/arm/Kconfig.debug

+1 −1
Original line number Diff line number Diff line
@@ -65,7 +65,7 @@ config UNWINDER_FRAME_POINTER 


config UNWINDER_ARM

	bool "ARM EABI stack unwinder"

	depends on AEABI && !FUNCTION_GRAPH_TRACER

	depends on AEABI

	# https://github.com/ClangBuiltLinux/linux/issues/732

	depends on !LD_IS_LLD || LLD_VERSION >= 110000

	select ARM_UNWIND

arch/arm/include/asm/cacheflush.h

+3 −9
Original line number Diff line number Diff line
@@ -446,15 +446,10 @@ static inline void __sync_cache_range_r(volatile void *p, size_t size) 
 *   however some exceptions may exist.  Caveat emptor.

 *

 * - The clobber list is dictated by the call to v7_flush_dcache_*.

 *   fp is preserved to the stack explicitly prior disabling the cache

 *   since adding it to the clobber list is incompatible with having

 *   CONFIG_FRAME_POINTER=y.  ip is saved as well if ever r12-clobbering

 *   trampoline are inserted by the linker and to keep sp 64-bit aligned.

 */

#define v7_exit_coherency_flush(level) \

	asm volatile( \

	".arch	armv7-a \n\t" \

	"stmfd	sp!, {fp, ip} \n\t" \

	"mrc	p15, 0, r0, c1, c0, 0	@ get SCTLR \n\t" \

	"bic	r0, r0, #"__stringify(CR_C)" \n\t" \

	"mcr	p15, 0, r0, c1, c0, 0	@ set SCTLR \n\t" \
@@ -464,10 +459,9 @@ static inline void __sync_cache_range_r(volatile void *p, size_t size) 
	"bic	r0, r0, #(1 << 6)	@ disable local coherency \n\t" \

	"mcr	p15, 0, r0, c1, c0, 1	@ set ACTLR \n\t" \

	"isb	\n\t" \

	"dsb	\n\t" \

	"ldmfd	sp!, {fp, ip}" \

	: : : "r0","r1","r2","r3","r4","r5","r6","r7", \

	      "r9","r10","lr","memory" )

	"dsb" \

	: : : "r0","r1","r2","r3","r4","r5","r6", \

	      "r9","r10","ip","lr","memory" )



void flush_uprobe_xol_access(struct page *page, unsigned long uaddr,

			     void *kaddr, unsigned long len);

arch/arm/include/asm/ftrace.h

+2 −18
Original line number Diff line number Diff line
@@ -2,6 +2,8 @@ 
#ifndef _ASM_ARM_FTRACE

#define _ASM_ARM_FTRACE



#define HAVE_FUNCTION_GRAPH_FP_TEST



#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS

#define ARCH_SUPPORTS_FTRACE_OPS 1

#endif
@@ -33,26 +35,8 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr) 


#ifndef __ASSEMBLY__



#if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND)

/*

 * return_address uses walk_stackframe to do it's work.  If both

 * CONFIG_FRAME_POINTER=y and CONFIG_ARM_UNWIND=y walk_stackframe uses unwind

 * information.  For this to work in the function tracer many functions would

 * have to be marked with __notrace.  So for now just depend on

 * !CONFIG_ARM_UNWIND.

 */



void *return_address(unsigned int);



#else



static inline void *return_address(unsigned int level)

{

	return NULL;

}



#endif



#define ftrace_return_address(n) return_address(n)



#define ARCH_HAS_SYSCALL_MATCH_SYM_NAME

arch/arm/include/asm/stacktrace.h

+3 −0
Original line number Diff line number Diff line
@@ -14,6 +14,9 @@ struct stackframe { 
	unsigned long sp;

	unsigned long lr;

	unsigned long pc;



	/* address of the LR value on the stack */

	unsigned long *lr_addr;

#ifdef CONFIG_KRETPROBES

	struct llist_node *kr_cur;

	struct task_struct *tsk;