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riscv: Restore floating-point caller saved registers before integer

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This fixes an issue where the t0 register is overwritten after it
has been restored.

Signed-off-by: Corey Wharton <coreyw7@fb.com>
This commit is contained in:
Corey Wharton 2020-04-14 14:56:12 -07:00 • committed by Andrew Boie
commit 6f6564752a
1 changed files with 22 additions and 18 deletions
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40
arch/riscv/core/isr.S
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@ -495,6 +495,15 @@ skip_store_fp_caller_saved_benchmark:
call read_timer_end_of_swap
#if defined(CONFIG_FLOAT) && defined(CONFIG_FP_SHARING)
/* Determine if we need to restore floating-point registers. */
RV_OP_LOADREG t2, __z_arch_esf_t_fp_state_OFFSET(sp)
beqz t2, skip_load_fp_caller_saved_benchmark
LOAD_FP_CALLER_SAVED(sp)
skip_load_fp_caller_saved_benchmark:
#endif
RV_OP_LOADREG ra, __z_arch_esf_t_ra_OFFSET(sp)
RV_OP_LOADREG gp, __z_arch_esf_t_gp_OFFSET(sp)
RV_OP_LOADREG tp, __z_arch_esf_t_tp_OFFSET(sp)
@ -514,15 +523,6 @@ skip_store_fp_caller_saved_benchmark:
RV_OP_LOADREG a6, __z_arch_esf_t_a6_OFFSET(sp)
RV_OP_LOADREG a7, __z_arch_esf_t_a7_OFFSET(sp)
#if defined(CONFIG_FLOAT) && defined(CONFIG_FP_SHARING)
/* Determine if we need to restore floating-point registers. */
RV_OP_LOADREG t2, __z_arch_esf_t_fp_state_OFFSET(sp)
beqz t2, skip_load_fp_caller_saved_benchmark
LOAD_FP_CALLER_SAVED(sp)
skip_load_fp_caller_saved_benchmark:
#endif
/* Release stack space */
addi sp, sp, __z_arch_esf_t_SIZEOF
#endif
@ -542,6 +542,19 @@ no_reschedule:
RV_OP_LOADREG t0, __z_arch_esf_t_mstatus_OFFSET(sp)
csrw mstatus, t0
#if defined(CONFIG_FLOAT) && defined(CONFIG_FP_SHARING)
/*
* Determine if we need to restore floating-point registers. This needs
* to happen before restoring integer registers to avoid stomping on
* t0.
*/
RV_OP_LOADREG t0, __z_arch_esf_t_fp_state_OFFSET(sp)
beqz t0, skip_load_fp_caller_saved
LOAD_FP_CALLER_SAVED(sp)
skip_load_fp_caller_saved:
#endif
/* Restore caller-saved registers from thread stack */
RV_OP_LOADREG ra, __z_arch_esf_t_ra_OFFSET(sp)
RV_OP_LOADREG gp, __z_arch_esf_t_gp_OFFSET(sp)
@ -562,15 +575,6 @@ no_reschedule:
RV_OP_LOADREG a6, __z_arch_esf_t_a6_OFFSET(sp)
RV_OP_LOADREG a7, __z_arch_esf_t_a7_OFFSET(sp)
#if defined(CONFIG_FLOAT) && defined(CONFIG_FP_SHARING)
/* Determine if we need to restore floating-point registers. */
RV_OP_LOADREG t0, __z_arch_esf_t_fp_state_OFFSET(sp)
beqz t0, skip_load_fp_caller_saved
LOAD_FP_CALLER_SAVED(sp)
skip_load_fp_caller_saved:
#endif
/* Release stack space */
addi sp, sp, __z_arch_esf_t_SIZEOF