[PATCH 6.6 053/396] parisc/unaligned: Rewrite 64-bit inline assembly of emulate_ldd()

Greg Kroah-Hartman
2024-04-01T16:37:38Z

From: Guenter Roeck <linux@roeck-us.net>

[ Upstream commit e5db6a74571a8baf87a116ea39aab946283362ff ]

Convert to use real temp variables instead of clobbering processor
registers. This aligns the 64-bit inline assembly code with the 32-bit
assembly code which was rewritten with commit 427c1073a2a1
("parisc/unaligned: Rewrite 32-bit inline assembly of emulate_ldd()").

While at it, fix comment in 32-bit rewrite code. Temporary variables are
now used for both 32-bit and 64-bit code, so move their declarations
to the function header.

No functional change intended.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Cc: stable@vger.kernel.org # v6.0+
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/parisc/kernel/unaligned.c | 27 ++++++++++++---------------
1 file changed, 12 insertions(+), 15 deletions(-)

diff --git a/arch/parisc/kernel/unaligned.c b/arch/parisc/kernel/unaligned.c
index c520e551a1652..a8e75e5b884a7 100644
--- a/arch/parisc/kernel/unaligned.c
+++ b/arch/parisc/kernel/unaligned.c
@@ -169,6 +169,7 @@ static int emulate_ldw(struct pt_regs *regs, int toreg, int flop)
static int emulate_ldd(struct pt_regs *regs, int toreg, int flop)
{
unsigned long saddr = regs->ior;
+ unsigned long shift, temp1;
__u64 val = 0;
ASM_EXCEPTIONTABLE_VAR(ret);

@@ -180,25 +181,22 @@ static int emulate_ldd(struct pt_regs *regs, int toreg, int flop)

#ifdef CONFIG_64BIT
__asm__ __volatile__ (
-" depd,z %3,60,3,%%r19\n" /* r19=(ofs&7)*8 */
-" mtsp %4, %%sr1\n"
-" depd %%r0,63,3,%3\n"
-"1: ldd 0(%%sr1,%3),%0\n"
-"2: ldd 8(%%sr1,%3),%%r20\n"
-" subi 64,%%r19,%%r19\n"
-" mtsar %%r19\n"
-" shrpd %0,%%r20,%%sar,%0\n"
+" depd,z %2,60,3,%3\n" /* shift=(ofs&7)*8 */
+" mtsp %5, %%sr1\n"
+" depd %%r0,63,3,%2\n"
+"1: ldd 0(%%sr1,%2),%0\n"
+"2: ldd 8(%%sr1,%2),%4\n"
+" subi 64,%3,%3\n"
+" mtsar %3\n"
+" shrpd %0,%4,%%sar,%0\n"
"3: \n"
ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 3b, "%1")
ASM_EXCEPTIONTABLE_ENTRY_EFAULT(2b, 3b, "%1")
- : "=r" (val), "+r" (ret)
- : "0" (val), "r" (saddr), "r" (regs->isr)
- : "r19", "r20" );
+ : "+r" (val), "+r" (ret), "+r" (saddr), "=&r" (shift), "=&r" (temp1)
+ : "r" (regs->isr) );
#else
- {
- unsigned long shift, temp1;
__asm__ __volatile__ (
-" zdep %2,29,2,%3\n" /* r19=(ofs&3)*8 */
+" zdep %2,29,2,%3\n" /* shift=(ofs&3)*8 */
" mtsp %5, %%sr1\n"
" dep %%r0,31,2,%2\n"
"1: ldw 0(%%sr1,%2),%0\n"
@@ -214,7 +212,6 @@ static int emulate_ldd(struct pt_regs *regs, int toreg, int flop)
ASM_EXCEPTIONTABLE_ENTRY_EFAULT(3b, 4b, "%1")
: "+r" (val), "+r" (ret), "+r" (saddr), "=&r" (shift), "=&r" (temp1)
: "r" (regs->isr) );
- }
#endif

DPRINTF("val = 0x%llx\n", val);
--
2.43.0