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parisc/unaligned: Fix fldd and fstd unaligned handlers on 32-bit kernel

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Usually the kernel provides fixup routines to emulate the fldd and fstd
floating-point instructions if they load or store 8-byte from/to a not
natuarally aligned memory location.

On a 32-bit kernel I noticed that those unaligned handlers didn't worked and
instead the application got a SEGV.
While checking the code I found two problems:

First, the OPCODE_FLDD_L and OPCODE_FSTD_L cases were ifdef'ed out by the
CONFIG_PA20 option, and as such those weren't built on a pure 32-bit kernel.
This is now fixed by moving the CONFIG_PA20 #ifdef to prevent the compilation
of OPCODE_LDD_L and OPCODE_FSTD_L only, and handling the fldd and fstd
instructions.

The second problem are two bugs in the 32-bit inline assembly code, where the
wrong registers where used. The calculation of the natural alignment used %2
(vall) instead of %3 (ior), and the first word was stored back to address %1
(valh) instead of %3 (ior).

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org
This commit is contained in:
Helge Deller 2022-02-18 09:25:20 +01:00
parent 8b97cae315
commit dd2288f4a0
1 changed files with 4 additions and 4 deletions
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8
arch/parisc/kernel/unaligned.c
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@ -397,7 +397,7 @@ static int emulate_std(struct pt_regs *regs, int frreg, int flop)
__asm__ __volatile__ (
" mtsp %4, %%sr1\n"
" zdep %2, 29, 2, %%r19\n"
" dep %%r0, 31, 2, %2\n"
" dep %%r0, 31, 2, %3\n"
" mtsar %%r19\n"
" zvdepi -2, 32, %%r19\n"
"1: ldw 0(%%sr1,%3),%%r20\n"
@ -409,7 +409,7 @@ static int emulate_std(struct pt_regs *regs, int frreg, int flop)
" andcm %%r21, %%r19, %%r21\n"
" or %1, %%r20, %1\n"
" or %2, %%r21, %2\n"
"3: stw %1,0(%%sr1,%1)\n"
"3: stw %1,0(%%sr1,%3)\n"
"4: stw %%r1,4(%%sr1,%3)\n"
"5: stw %2,8(%%sr1,%3)\n"
" copy %%r0, %0\n"
@ -596,7 +596,6 @@ void handle_unaligned(struct pt_regs *regs)
ret = ERR_NOTHANDLED; /* "undefined", but lets kill them. */
break;
}
#ifdef CONFIG_PA20
switch (regs->iir & OPCODE2_MASK)
{
case OPCODE_FLDD_L:
@ -607,14 +606,15 @@ void handle_unaligned(struct pt_regs *regs)
flop=1;
ret = emulate_std(regs, R2(regs->iir),1);
break;
#ifdef CONFIG_PA20
case OPCODE_LDD_L:
ret = emulate_ldd(regs, R2(regs->iir),0);
break;
case OPCODE_STD_L:
ret = emulate_std(regs, R2(regs->iir),0);
break;
}
#endif
}
switch (regs->iir & OPCODE3_MASK)
{
case OPCODE_FLDW_L: