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ARM: P2V: extend to 16-bit translation offsets 

MSM's memory is aligned to 2MB, which is more than we can do with our
existing method as we're limited to the upper 8 bits.  Extend this by
using two instructions to 16 bits, automatically selected when MSM is
enabled.

Acked-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Tested-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
hifive-unleashed-5.1
Russell King 2011-01-04 19:39:29 +00:00
parent dc21af99fa
commit cada3c0841
4 changed files with 39 additions and 6 deletions
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5
arch/arm/Kconfig
View File

@ -195,7 +195,6 @@ config ARM_PATCH_PHYS_VIRT
bool "Patch physical to virtual translations at runtime (EXPERIMENTAL)"
depends on EXPERIMENTAL
depends on !XIP_KERNEL && !THUMB2_KERNEL && MMU
depends on !ARCH_MSM
depends on !ARCH_REALVIEW || !SPARSEMEM
help
Patch phys-to-virt translation functions at runtime according to
@ -204,6 +203,10 @@ config ARM_PATCH_PHYS_VIRT
This can only be used with non-XIP, non-Thumb2, MMU kernels where
the base of physical memory is at a 16MB boundary.
config ARM_PATCH_PHYS_VIRT_16BIT
def_bool y
depends on ARM_PATCH_PHYS_VIRT && ARCH_MSM
source "init/Kconfig"
source "kernel/Kconfig.freezer"

21
arch/arm/include/asm/memory.h
View File

@ -154,29 +154,42 @@
#ifndef __virt_to_phys
#ifdef CONFIG_ARM_PATCH_PHYS_VIRT
/*
* Constants used to force the right instruction encodings and shifts
* so that all we need to do is modify the 8-bit constant field.
*/
#define __PV_BITS_31_24 0x81000000
#define __PV_BITS_23_16 0x00810000
extern unsigned long __pv_phys_offset;
#define PHYS_OFFSET __pv_phys_offset
#define __pv_stub(from,to,instr) \
#define __pv_stub(from,to,instr,type) \
__asm__("@ __pv_stub\n" \
"1: " instr " %0, %1, %2\n" \
" .pushsection .pv_table,\"a\"\n" \
" .long 1b\n" \
" .popsection\n" \
: "=r" (to) \
: "r" (from), "I" (0x81000000))
: "r" (from), "I" (type))
static inline unsigned long __virt_to_phys(unsigned long x)
{
unsigned long t;
__pv_stub(x, t, "add");
__pv_stub(x, t, "add", __PV_BITS_31_24);
#ifdef CONFIG_ARM_PATCH_PHYS_VIRT_16BIT
__pv_stub(t, t, "add", __PV_BITS_23_16);
#endif
return t;
}
static inline unsigned long __phys_to_virt(unsigned long x)
{
unsigned long t;
__pv_stub(x, t, "sub");
__pv_stub(x, t, "sub", __PV_BITS_31_24);
#ifdef CONFIG_ARM_PATCH_PHYS_VIRT_16BIT
__pv_stub(t, t, "sub", __PV_BITS_23_16);
#endif
return t;
}
#else

4
arch/arm/include/asm/module.h
View File

@ -31,7 +31,11 @@ struct mod_arch_specific {
/* Add __virt_to_phys patching state as well */
#ifdef CONFIG_ARM_PATCH_PHYS_VIRT
#ifdef CONFIG_ARM_PATCH_PHYS_VIRT_16BIT
#define MODULE_ARCH_VERMAGIC_P2V "p2v16 "
#else
#define MODULE_ARCH_VERMAGIC_P2V "p2v8 "
#endif
#else
#define MODULE_ARCH_VERMAGIC_P2V ""
#endif

15
arch/arm/kernel/head.S
View File

@ -456,8 +456,13 @@ __fixup_pv_table:
add r4, r4, r3 @ adjust table start address
add r5, r5, r3 @ adjust table end address
str r8, [r7, r3]! @ save computed PHYS_OFFSET to __pv_phys_offset
#ifndef CONFIG_ARM_PATCH_PHYS_VIRT_16BIT
mov r6, r3, lsr #24 @ constant for add/sub instructions
teq r3, r6, lsl #24 @ must be 16MiB aligned
#else
mov r6, r3, lsr #16 @ constant for add/sub instructions
teq r3, r6, lsl #16 @ must be 64kiB aligned
#endif
bne __error
str r6, [r7, #4] @ save to __pv_offset
b __fixup_a_pv_table
@ -471,10 +476,18 @@ ENDPROC(__fixup_pv_table)
.text
__fixup_a_pv_table:
#ifdef CONFIG_ARM_PATCH_PHYS_VIRT_16BIT
and r0, r6, #255 @ offset bits 23-16
mov r6, r6, lsr #8 @ offset bits 31-24
#else
mov r0, #0 @ just in case...
#endif
b 3f
2: ldr ip, [r7, r3]
bic ip, ip, #0x000000ff
orr ip, ip, r6
tst ip, #0x400 @ rotate shift tells us LS or MS byte
orrne ip, ip, r6 @ mask in offset bits 31-24
orreq ip, ip, r0 @ mask in offset bits 23-16
str ip, [r7, r3]
3: cmp r4, r5
ldrcc r7, [r4], #4 @ use branch for delay slot