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RISC-V: reduce mcount save space on RV32 

For RV32 we can reduce the size of the ABI save+restore state by using
SZREG so that register stores are packed rather than on an 8 byte
boundary.

Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20221115200832.706370-3-jamie@jamieiles.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Jamie Iles 2022-11-15 20:08:30 +00:00 committed by Palmer Dabbelt
parent 8a6841c439
commit 3bd7743f8d
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GPG Key ID: 2E1319F35FBB1889
1 changed files with 16 additions and 16 deletions
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32
arch/riscv/kernel/mcount.S
View File

@ -15,8 +15,8 @@
.macro SAVE_ABI_STATE
addi sp, sp, -16
REG_S s0, 0(sp)
REG_S ra, 8(sp)
REG_S s0, 0*SZREG(sp)
REG_S ra, 1*SZREG(sp)
addi s0, sp, 16
.endm
@ -25,24 +25,24 @@
* register if a0 was not saved.
*/
.macro SAVE_RET_ABI_STATE
addi sp, sp, -32
REG_S s0, 16(sp)
REG_S ra, 24(sp)
REG_S 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)
addi s0, sp, 4*SZREG
.endm
.macro RESTORE_ABI_STATE
REG_L ra, 8(sp)
REG_L 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
REG_L ra, 24(sp)
REG_L s0, 16(sp)
REG_L 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)
addi sp, sp, 4*SZREG
.endm
ENTRY(ftrace_stub)
@ -101,10 +101,10 @@ 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
REG_L a2, -16(s0)
REG_L a2, -2*SZREG(s0)
#endif
SAVE_ABI_STATE
call prepare_ftrace_return
@ -117,7 +117,7 @@ do_ftrace_graph_caller:
* (*ftrace_trace_function)(ra_to_caller, ra_to_caller_of_caller)
*/
do_trace:
REG_L a1, -8(s0)
REG_L a1, -SZREG(s0)
mv a0, ra
SAVE_ABI_STATE