forked from Minki/linux
6ebbf2ce43
ARMv6 and greater introduced a new instruction ("bx") which can be used
to return from function calls. Recent CPUs perform better when the
"bx lr" instruction is used rather than the "mov pc, lr" instruction,
and this sequence is strongly recommended to be used by the ARM
architecture manual (section A.4.1.1).
We provide a new macro "ret" with all its variants for the condition
code which will resolve to the appropriate instruction.
Rather than doing this piecemeal, and miss some instances, change all
the "mov pc" instances to use the new macro, with the exception of
the "movs" instruction and the kprobes code. This allows us to detect
the "mov pc, lr" case and fix it up - and also gives us the possibility
of deploying this for other registers depending on the CPU selection.
Reported-by: Will Deacon <will.deacon@arm.com>
Tested-by: Stephen Warren <swarren@nvidia.com> # Tegra Jetson TK1
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr> # mioa701_bootresume.S
Tested-by: Andrew Lunn <andrew@lunn.ch> # Kirkwood
Tested-by: Shawn Guo <shawn.guo@freescale.com>
Tested-by: Tony Lindgren <tony@atomide.com> # OMAPs
Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com> # Armada XP, 375, 385
Acked-by: Sekhar Nori <nsekhar@ti.com> # DaVinci
Acked-by: Christoffer Dall <christoffer.dall@linaro.org> # kvm/hyp
Acked-by: Haojian Zhuang <haojian.zhuang@gmail.com> # PXA3xx
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> # Xen
Tested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> # ARMv7M
Tested-by: Simon Horman <horms+renesas@verge.net.au> # Shmobile
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
94 lines
1.4 KiB
ArmAsm
94 lines
1.4 KiB
ArmAsm
/*
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* relocate_kernel.S - put the kernel image in place to boot
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*/
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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#include <asm/kexec.h>
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.align 3 /* not needed for this code, but keeps fncpy() happy */
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ENTRY(relocate_new_kernel)
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ldr r0,kexec_indirection_page
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ldr r1,kexec_start_address
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/*
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* If there is no indirection page (we are doing crashdumps)
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* skip any relocation.
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*/
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cmp r0, #0
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beq 2f
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0: /* top, read another word for the indirection page */
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ldr r3, [r0],#4
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/* Is it a destination page. Put destination address to r4 */
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tst r3,#1,0
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beq 1f
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bic r4,r3,#1
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b 0b
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1:
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/* Is it an indirection page */
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tst r3,#2,0
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beq 1f
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bic r0,r3,#2
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b 0b
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1:
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/* are we done ? */
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tst r3,#4,0
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beq 1f
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b 2f
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1:
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/* is it source ? */
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tst r3,#8,0
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beq 0b
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bic r3,r3,#8
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mov r6,#1024
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9:
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ldr r5,[r3],#4
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str r5,[r4],#4
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subs r6,r6,#1
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bne 9b
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b 0b
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2:
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/* Jump to relocated kernel */
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mov lr,r1
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mov r0,#0
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ldr r1,kexec_mach_type
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ldr r2,kexec_boot_atags
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ARM( ret lr )
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THUMB( bx lr )
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.align
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.globl kexec_start_address
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kexec_start_address:
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.long 0x0
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.globl kexec_indirection_page
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kexec_indirection_page:
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.long 0x0
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.globl kexec_mach_type
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kexec_mach_type:
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.long 0x0
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/* phy addr of the atags for the new kernel */
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.globl kexec_boot_atags
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kexec_boot_atags:
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.long 0x0
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ENDPROC(relocate_new_kernel)
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relocate_new_kernel_end:
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.globl relocate_new_kernel_size
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relocate_new_kernel_size:
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.long relocate_new_kernel_end - relocate_new_kernel
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