mirror of https://gitee.com/openkylin/linux.git
5756e9dd0d
In low-level board support code, there is sometimes a need to copy a function body to another location at run-time. A straightforward call to memcpy doesn't work in Thumb-2, because bit 0 of external Thumb function symbols is set to 1, indicating that the function is Thumb. Without corrective measures, this will cause an off-by-one copy, and the copy may be called using the wrong instruction set. This patch adds an fncpy() macro to help with such copies. Particular care is needed, because C doesn't guarantee any defined behaviour when casting a function pointer to any other type. This has been observed to lead to strange optimisation side-effects when doing the arithmetic which is required in order to copy/move function bodies correctly in Thumb-2. Thanks to Russell King and Nicolas Pitre for their input on this patch. Signed-off-by: Dave Martin <dave.martin@linaro.org> Tested-by: Jean Pihet <j-pihet@ti.com> Tested-by: Tony Lindgren <tony@atomide.com> Tested-by: Kevin Hilman <khilman@ti.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> |
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| alpha | ||
| arm | ||
| avr32 | ||
| blackfin | ||
| cris | ||
| frv | ||
| h8300 | ||
| ia64 | ||
| m32r | ||
| m68k | ||
| m68knommu | ||
| microblaze | ||
| mips | ||
| mn10300 | ||
| parisc | ||
| powerpc | ||
| s390 | ||
| score | ||
| sh | ||
| sparc | ||
| tile | ||
| um | ||
| x86 | ||
| xtensa | ||
| .gitignore | ||
| Kconfig | ||