Generate illegal instruction fault if LWS syscall returns -EFAULT.

2022-01-02  John David Anglin  <danglin@gcc.gnu.org>

libgcc/ChangeLog:

	* config/pa/linux-atomic.c (_ASM_EFAULT): Define.
	(__kernel_cmpxchg): Nullify illegal iitlbp instruction if error
	return is not equal _ASM_EFAULT.
	(__kernel_cmpxchg2): Likewise.

diff --git a/libgcc/config/pa/linux-atomic.c b/libgcc/config/pa/linux-atomic.c
index 500a365..e4d74b2 100644 (file)
--- a/libgcc/config/pa/linux-atomic.c
+++ b/libgcc/config/pa/linux-atomic.c
@@ -28,6 +28,8 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define EBUSY   16
 #define ENOSYS 251 
 
+#define _ASM_EFAULT "-14"
+
 typedef unsigned char u8;
 typedef short unsigned int u16;
 #ifdef __LP64__
@@ -58,6 +60,8 @@ __kernel_cmpxchg (volatile void *mem, int oldval, int newval)
   register long lws_errno asm("r21");
   asm volatile (       "ble    0xb0(%%sr2, %%r0)       \n\t"
                        "ldi    %2, %%r20               \n\t"
+                       "cmpiclr,<> " _ASM_EFAULT ", %%r21, %%r0\n\t"
+                       "iitlbp %%r0,(%%sr0, %%r0)      \n\t"
        : "=r" (lws_ret), "=r" (lws_errno)
        : "i" (LWS_CAS), "r" (lws_mem), "r" (lws_old), "r" (lws_new)
        : "r1", "r20", "r22", "r23", "r29", "r31", "memory"
@@ -84,6 +88,8 @@ __kernel_cmpxchg2 (volatile void *mem, const void *oldval, const void *newval,
   register long lws_errno asm("r21");
   asm volatile (       "ble    0xb0(%%sr2, %%r0)       \n\t"
                        "ldi    %6, %%r20               \n\t"
+                       "cmpiclr,<> " _ASM_EFAULT ", %%r21, %%r0\n\t"
+                       "iitlbp %%r0,(%%sr0, %%r0)      \n\t"
        : "=r" (lws_ret), "=r" (lws_errno), "+r" (lws_mem),
          "+r" (lws_old), "+r" (lws_new), "+r" (lws_size)
        : "i" (2)