According to the PARISC 1.1 Instruction Set Reference Manual, PA1.1 does
*not* support the depw,z instruction, but only the dep (depw)
instruction, e.g.:
d5 8b 08 f6 depw,z r11,24,10,r12 # NOT PA1.1
d5 8b 0c f6 depw r11,24,10,r12 # OK for PA1.1
And in the Linux kernel source (arch/parisc/include/asm/assembly.h) I see
/* Shift Left - note the r and t can NOT be the same! */
.macro shl r, sa, t
dep,z \r, 31-(\sa), 32-(\sa), \t
.endm
(by the way, this macro isn't used and correctly doesn't compile because
of the z completer)
But when I disassemble the kernel source code (built for PA1.1), I see
lots of depw,z instructions generated by gcc, e.g.:
d4 84 09 8c depw,z r4,19,20,r4
So, what's true?
For the shl macro, can't r and t not be the same, because then on
PA1.1 the shl leaves the rightmost bits untouched/not-zeroed in t?
Qemu, which emulates a PA1.1, seems to happily translate even the
depw,z instruction.
Do we maybe need a patch like the one below (and teach gcc not to emit
depw,z) to be fully PA1.1 compatible?
Suggestions?
Helge
The patch below should make the kernel fully PA1.1 compatible.
diff --git a/arch/parisc/include/asm/assembly.h b/arch/parisc/include/asm/assembly.h
index 60e6f07b7e32..87980fd1c4f1 100644
--- a/arch/parisc/include/asm/assembly.h
+++ b/arch/parisc/include/asm/assembly.h
@@ -44,7 +44,7 @@
#define LDREGM ldwm
#define STREGM stwm
#define SHRREG shr
-#define SHLREG shlw
+#define SHLREG shl
#define ANDCM andcm
#define COND(x) x
#define RP_OFFSET 20
@@ -128,14 +128,15 @@
.endm
- /* Shift Left - note the r and t can NOT be the same! */
.macro shl r, sa, t
- dep,z \r, 31-(\sa), 32-(\sa), \t
- .endm
-
- /* The PA 2.0 shift left */
- .macro shlw r, sa, t
+#ifdef CONFIG_PA20
+ /* The PA 2.0 shift left (shlw) */
depw,z \r, 31-(\sa), 32-(\sa), \t
+#else
+ /* PA 1.0 Shift Left - note the r and t can NOT be the same! */
+ copy %r0, \t
+ dep \r, 31-(\sa), 32-(\sa), \t
+#endif
.endm
/* And the PA 2.0W shift left */
diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
index 1b4732e20137..dca15d4d1d70 100644
--- a/arch/parisc/kernel/entry.S
+++ b/arch/parisc/kernel/entry.S
@@ -421,12 +421,16 @@
# endif
#endif
dep %r0,31,PAGE_SHIFT,\pmd /* clear offset */
- copy %r0,\pte
ldw,s \index(\pmd),\pmd
bb,>=,n \pmd,_PxD_PRESENT_BIT,\fault
dep %r0,31,PxD_FLAG_SHIFT,\pmd /* clear flags */
- copy \pmd,%r9
- SHLREG %r9,PxD_VALUE_SHIFT,\pmd
+#ifdef CONFIG_PA20
+ SHLREG \pmd,PxD_VALUE_SHIFT,\pmd
+#else
+ copy \pmd,\pte
+ SHLREG \pte,PxD_VALUE_SHIFT,\pmd
+#endif
+ copy %r0,\pte
extru \va,31-PAGE_SHIFT,ASM_BITS_PER_PTE,\index
dep %r0,31,PAGE_SHIFT,\pmd /* clear offset */
shladd \index,BITS_PER_PTE_ENTRY,\pmd,\pmd /* pmd is now pte */
@@ -447,7 +451,6 @@
.macro L3_ptep pgd,pte,index,va,fault
#if CONFIG_PGTABLE_LEVELS == 3 /* we might have a 2-Level scheme, e.g. with 16kb page size */
extrd,u \va,63-ASM_PGDIR_SHIFT,ASM_BITS_PER_PGD,\index
- copy %r0,\pte
extrd,u,*= \va,63-ASM_PGDIR_SHIFT,64-ASM_PGDIR_SHIFT,%r0
ldw,s \index(\pgd),\pgd
extrd,u,*= \va,63-ASM_PGDIR_SHIFT,64-ASM_PGDIR_SHIFT,%r0
diff --git a/arch/parisc/kernel/syscall.S b/arch/parisc/kernel/syscall.S
index 5f7e57fcaeef..37fb08a48504 100644
--- a/arch/parisc/kernel/syscall.S
+++ b/arch/parisc/kernel/syscall.S
@@ -570,8 +570,8 @@ lws_compare_and_swap:
/* Find lock to use, the hash is either one of 0 to
15, multiplied by 16 (keep it 16-byte aligned)
and add to the lock table offset. */
- shlw %r20, 4, %r20
- add %r20, %r28, %r20
+ SHLREG %r20, 4, %r21
+ add %r21, %r28, %r20
# if ENABLE_LWS_DEBUG
/*
@@ -705,7 +705,7 @@ lws_compare_and_swap_2:
/* Jump to the functions which will load the old and new values into
registers depending on the their size */
- shlw %r23, 2, %r29
+ SHLREG %r23, 2, %r29
blr %r29, %r0
nop
@@ -762,8 +762,8 @@ cas2_lock_start:
/* Find lock to use, the hash is either one of 0 to
15, multiplied by 16 (keep it 16-byte aligned)
and add to the lock table offset. */
- shlw %r20, 4, %r20
- add %r20, %r28, %r20
+ SHLREG %r20, 4, %r21
+ add %r21, %r28, %r20
rsm PSW_SM_I, %r0 /* Disable interrupts */
/* COW breaks can cause contention on UP systems */
