Unverified Commit 5f66e187 authored by Palmer Dabbelt's avatar Palmer Dabbelt
Browse files

Merge patch series "RISC-V: Dynamic ftrace support for RV32I" 

Jamie Iles <jamie@jamieiles.com> says:

This series enables dynamic ftrace support for RV32I bringing it to
parity with RV64I.  Most of the work is already there, this is largely
just assembly fixes to handle register sizes, correct handling of the
psABI calling convention and Kconfig change.

Validated with all ftrace boot time self test with qemu for RV32I and
RV64I in addition to real tracing on an RV32I FPGA design.

* b4-shazam-merge:
  RISC-V: enable dynamic ftrace for RV32I
  RISC-V: preserve a1 in mcount
  RISC-V: reduce mcount save space on RV32
  RISC-V: use REG_S/REG_L for mcount

Link: https://lore.kernel.org/r/20221115200832.706370-1-jamie@jamieiles.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parents 41555cc9 f32b4b46

arch/riscv/Kconfig

+5 −5
Original line number Diff line number Diff line
@@ -131,6 +131,11 @@ config RISCV 
	select TRACE_IRQFLAGS_SUPPORT

	select UACCESS_MEMCPY if !MMU

	select ZONE_DMA32 if 64BIT

	select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU && $(cc-option,-fpatchable-function-entry=8)

	select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE

	select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL

	select HAVE_FUNCTION_GRAPH_TRACER

	select HAVE_FUNCTION_TRACER if !XIP_KERNEL



config ARCH_MMAP_RND_BITS_MIN

	default 18 if 64BIT
@@ -276,11 +281,6 @@ config ARCH_RV64I 
	bool "RV64I"

	select 64BIT

	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128

	select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU && $(cc-option,-fpatchable-function-entry=8)

	select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE

	select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL

	select HAVE_FUNCTION_GRAPH_TRACER

	select HAVE_FUNCTION_TRACER if !XIP_KERNEL

	select SWIOTLB if MMU



endchoice

arch/riscv/kernel/mcount.S

+23 −21
Original line number Diff line number Diff line
@@ -15,8 +15,8 @@ 


	.macro SAVE_ABI_STATE

	addi	sp, sp, -16

	sd	s0, 0(sp)

	sd	ra, 8(sp)

	REG_S	s0, 0*SZREG(sp)

	REG_S	ra, 1*SZREG(sp)

	addi	s0, sp, 16

	.endm
@@ -25,24 +25,26 @@ 
	 * register if a0 was not saved.

	 */

	.macro SAVE_RET_ABI_STATE

	addi	sp, sp, -32

	sd	s0, 16(sp)

	sd	ra, 24(sp)

	sd	a0, 8(sp)

	addi	s0, sp, 32

	addi	sp, sp, -4*SZREG

	REG_S	s0, 2*SZREG(sp)

	REG_S	ra, 3*SZREG(sp)

	REG_S	a0, 1*SZREG(sp)

	REG_S	a1, 0*SZREG(sp)

	addi	s0, sp, 4*SZREG

	.endm



	.macro RESTORE_ABI_STATE

	ld	ra, 8(sp)

	ld	s0, 0(sp)

	REG_L	ra, 1*SZREG(sp)

	REG_L	s0, 0*SZREG(sp)

	addi	sp, sp, 16

	.endm



	.macro RESTORE_RET_ABI_STATE

	ld	ra, 24(sp)

	ld	s0, 16(sp)

	ld	a0, 8(sp)

	addi	sp, sp, 32

	REG_L	ra, 3*SZREG(sp)

	REG_L	s0, 2*SZREG(sp)

	REG_L	a0, 1*SZREG(sp)

	REG_L	a1, 0*SZREG(sp)

	addi	sp, sp, 4*SZREG

	.endm



ENTRY(ftrace_stub)
@@ -71,9 +73,9 @@ ENTRY(return_to_handler) 
	mv	a0, t6

#endif

	call	ftrace_return_to_handler

	mv	a1, a0

	mv	a2, a0

	RESTORE_RET_ABI_STATE

	jalr	a1

	jalr	a2

ENDPROC(return_to_handler)

#endif
@@ -82,16 +84,16 @@ ENTRY(MCOUNT_NAME) 
	la	t4, ftrace_stub

#ifdef CONFIG_FUNCTION_GRAPH_TRACER

	la	t0, ftrace_graph_return

	ld	t1, 0(t0)

	REG_L	t1, 0(t0)

	bne	t1, t4, do_ftrace_graph_caller



	la	t3, ftrace_graph_entry

	ld	t2, 0(t3)

	REG_L	t2, 0(t3)

	la	t6, ftrace_graph_entry_stub

	bne	t2, t6, do_ftrace_graph_caller

#endif

	la	t3, ftrace_trace_function

	ld	t5, 0(t3)

	REG_L	t5, 0(t3)

	bne	t5, t4, do_trace

	ret
@@ -101,10 +103,10 @@ ENTRY(MCOUNT_NAME) 
 * prepare_to_return(&ra_to_caller_of_caller, ra_to_caller)

 */

do_ftrace_graph_caller:

	addi	a0, s0, -8

	addi	a0, s0, -SZREG

	mv	a1, ra

#ifdef HAVE_FUNCTION_GRAPH_FP_TEST

	ld	a2, -16(s0)

	REG_L	a2, -2*SZREG(s0)

#endif

	SAVE_ABI_STATE

	call	prepare_ftrace_return
@@ -117,7 +119,7 @@ do_ftrace_graph_caller: 
 * (*ftrace_trace_function)(ra_to_caller, ra_to_caller_of_caller)

 */

do_trace:

	ld	a1, -8(s0)

	REG_L	a1, -SZREG(s0)

	mv	a0, ra



	SAVE_ABI_STATE