WSL2-Linux-Kernel/arch/arm/kernel/relocate_kernel.S

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1.4 KiB
ArmAsm
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/*
* relocate_kernel.S - put the kernel image in place to boot
*/
#include <linux/linkage.h>
ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 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>
2014-06-30 19:29:12 +04:00
#include <asm/assembler.h>
#include <asm/kexec.h>
.align 3 /* not needed for this code, but keeps fncpy() happy */
ENTRY(relocate_new_kernel)
ldr r0,kexec_indirection_page
ldr r1,kexec_start_address
/*
* If there is no indirection page (we are doing crashdumps)
* skip any relocation.
*/
cmp r0, #0
beq 2f
0: /* top, read another word for the indirection page */
ldr r3, [r0],#4
/* Is it a destination page. Put destination address to r4 */
tst r3,#1,0
beq 1f
bic r4,r3,#1
b 0b
1:
/* Is it an indirection page */
tst r3,#2,0
beq 1f
bic r0,r3,#2
b 0b
1:
/* are we done ? */
tst r3,#4,0
beq 1f
b 2f
1:
/* is it source ? */
tst r3,#8,0
beq 0b
bic r3,r3,#8
mov r6,#1024
9:
ldr r5,[r3],#4
str r5,[r4],#4
subs r6,r6,#1
bne 9b
b 0b
2:
/* Jump to relocated kernel */
mov lr,r1
mov r0,#0
ldr r1,kexec_mach_type
ldr r2,kexec_boot_atags
ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 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>
2014-06-30 19:29:12 +04:00
ARM( ret lr )
THUMB( bx lr )
.align
.globl kexec_start_address
kexec_start_address:
.long 0x0
.globl kexec_indirection_page
kexec_indirection_page:
.long 0x0
.globl kexec_mach_type
kexec_mach_type:
.long 0x0
/* phy addr of the atags for the new kernel */
.globl kexec_boot_atags
kexec_boot_atags:
[ARM] 4599/1: Preserve ATAG list for use with kexec (2.6.23) This patch resolves a kexec boot failure that can occur because no ATAGs are passed in to the kexec'd kernel. Currently the newly-kexec'd kernel may fail if it requires specific ATAGs, or it may fail because the fixed memory location at which it expects to find the ATAGs may contain random data instead of ATAGs. The patch ensures that any ATAGs passed to the current kernel at boot time are copied to a static buffer, and are copied back when kexec copies the new kernel into place. Thus the new kernel sees the same ATAGs from kexec and the boot loader. The boot parameters are copied without regard to type, content, or length -- this patch's scope is limited soley to saving and restoring a fixed-size block of memory containing the kernel's boot parameters. Additional functionality to examine, alter, or replace the ATAGs (using kexec, for example) can be implemented by manipulating the static buffer containing the preserved ATAGs. Note: the size of the buffer (1.5KB) is selected to comfortably hold one of each ATAG type, including a maximum-length command line and the maximum number of ATAG_MEM structures currently supported by the kernel. Should an ATAG list exceed that limit, the list will be silently truncated to that limit (to do other- wise at that point in the boot process would make a simple problem exceedingly complicated). [Note: this is the same patch as 4579, modified to accomodate the ATAG changes introduced in 2.6.23] Signed-off-by: Mike Westerhof <mwester at dls.net> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-10-11 06:18:14 +04:00
.long 0x0
ENDPROC(relocate_new_kernel)
relocate_new_kernel_end:
.globl relocate_new_kernel_size
relocate_new_kernel_size:
.long relocate_new_kernel_end - relocate_new_kernel