From a38187051863cf4a423c4f00669c6786bc8ff60d Mon Sep 17 00:00:00 2001 From: "Maksim E. Kozlov" Date: Wed, 5 Jun 2019 22:22:36 +0300 Subject: [PATCH] sparc: Fix missed restoring of PSR in syscall_lazy_fp_switch It is needed to restore PSR just before return because condition codes are dirty after the CMP instructions and this may cause undefined program behavior after returning from the switching procedure (on following branch instruction, for example). Close #3756. --- cpukit/score/cpu/sparc/syscall.S | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/cpukit/score/cpu/sparc/syscall.S b/cpukit/score/cpu/sparc/syscall.S index 603ed7a738..4f4ef32c53 100644 --- a/cpukit/score/cpu/sparc/syscall.S +++ b/cpukit/score/cpu/sparc/syscall.S @@ -241,12 +241,23 @@ SYM(syscall_lazy_fp_switch): .Lfp_restore_done: + /* + * Restore condition codes. PSR[EF] is 1 here. Take PSR write delay + * into account (maximum is three instructions). + */ + mov %l0, %psr + nop + /* Now, retry the floating point instruction with PSR[EF] == 1 */ jmp %l1 rett %l2 .Lillegal_use_of_floating_point_unit: + /* + * There is no need to restore the condition codes here, since + * _Internal_error() does not return. + */ sethi %hi(_Internal_error), %l1 or %l1, %lo(_Internal_error), %l1 mov 38, %i0