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2015-05-08ARM: replace BSYM() with badr assembly macroRussell King
BSYM() was invented to allow us to work around a problem with the assembler, where local symbols resolved by the assembler for the 'adr' instruction did not take account of their ISA. Since we don't want BSYM() used elsewhere, replace BSYM() with a new macro 'badr', which is like the 'adr' pseudo-op, but with the BSYM() mechanics integrated into it. This ensures that the BSYM()-ification is only used in conjunction with 'adr'. Acked-by: Dave Martin <Dave.Martin@arm.com> Acked-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-07-18ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+Russell King
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>
2011-12-12ARM: lib: add call_with_stack function for safely changing stackWill Deacon
When disabling the MMU, it is necessary to take out a 1:1 identity map of the reset code so that it can safely be executed with and without the MMU active. To avoid the situation where the physical address of the reset code aliases with the virtual address of the active stack (which cannot be included in the 1:1 mapping), it is desirable to change to a new stack at a location which is less likely to alias. This code adds a new lib function, call_with_stack: void call_with_stack(void (*fn)(void *), void *arg, void *sp); which changes the stack to point at the sp parameter, before invoking fn(arg) with the new stack selected. Reviewed-by: Nicolas Pitre <nicolas.pitre@linaro.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Dave Martin <dave.martin@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>