[newlib-cygwin] pru: Fix memory corruption on syscall return

[newlib-cygwin] pru: Fix memory corruption on syscall return

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=70cd4cbe651388897539fe38d2610e9bb733c5a8

commit 70cd4cbe651388897539fe38d2610e9bb733c5a8
Author: Dimitar Dimitrov <dimitar@dinux.eu>
Date:   Wed Jun 3 19:14:22 2020 +0300

    pru: Fix memory corruption on syscall return
    
    In the initial code I missed one level of pointer indirection. Instead
    of storing errno in impure_data, _impure_ptr was corrupted.
    
    Only simulator is impacted. Real targets have no OS and no syscalls.
    
    This resolves a bunch of stdio cases from the GCC testsuite:
      FAIL->PASS: gcc.c-torture/execute/printf-2.c   -O0  execution test
    
    Signed-off-by: Dimitar Dimitrov <dimitar@dinux.eu>

Diff:
---
 libgloss/pru/syscalls.S | 1 +
 1 file changed, 1 insertion(+)

diff --git a/libgloss/pru/syscalls.S b/libgloss/pru/syscalls.S
index 8ed7601a4..3ad0d9215 100644
--- a/libgloss/pru/syscalls.S
+++ b/libgloss/pru/syscalls.S
@@ -42,6 +42,7 @@ __SC_ret:
 	/* Invert return code and store to errno (first int in _impure_ptr).  */
 	rsb	r14, r14, 0
 	ldi32	r1, _impure_ptr
+	lbbo	r1, r1, 0, 4
 	sbbo	r14, r1, 0, 4
 	/* Return -1 (for both int32_t or int64_t).  */
 	fill	r14, 8