sparc64: Fix sun4u execute bit check in TSB I-TLB load.
Thanks to testcase and report from Brad Spengler:
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#include <stdio.h>
typedef int (* _wee)(void);
int main(void)
{
char buf[8] = { '\x81', '\xc7', '\xe0', '\x08', '\x81', '\xe8',
'\x00', '\x00' };
_wee wee;
printf("%p\n", &buf);
wee = (_wee)&buf;
wee();
return 0;
}
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TSB I-tlb load code tries to use andcc to check the _PAGE_EXEC_4U bit,
but that's bit 12 so it gets sign extended all the way up to bit 63
and the test nearly always passes as a result.
Use sethi to fix the bug.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/sparc/kernel/tsb.S b/arch/sparc/kernel/tsb.S
index 8c91d9b..db15d12 100644
--- a/arch/sparc/kernel/tsb.S
+++ b/arch/sparc/kernel/tsb.S
@@ -191,10 +191,12 @@
tsb_itlb_load:
/* Executable bit must be set. */
-661: andcc %g5, _PAGE_EXEC_4U, %g0
- .section .sun4v_1insn_patch, "ax"
+661: sethi %hi(_PAGE_EXEC_4U), %g4
+ andcc %g5, %g4, %g0
+ .section .sun4v_2insn_patch, "ax"
.word 661b
andcc %g5, _PAGE_EXEC_4V, %g0
+ nop
.previous
be,pn %xcc, tsb_do_fault