On Tue, Oct 5, 2021 at 9:00 PM <ckim@xxxxxxxxxx> wrote: > > In linux-5.4.21 code, > > To prevent some variables from being ‘optimized out’ during kernel code analysis using gdb, I added in drivers/iommu/Makefile, > > (replacing -O2 flags to -O0 flags for some files, I found http://www.joelfernandes.org/linux/2018/06/10/kernel-gdb.html ) > > CFLAGS_REMOVE_arm-smmu.o := -O2 > > CFLAGS_REMOVE_arm-smmu-impl.o := -O2 > > CFLAGS_REMOVE_io-pgtable-arm-v7s.o := -O2 > > CFLAGS_REMOVE_io-pgtable-arm.o := -O2 > > CFLAGS_REMOVE_of_iommu.o := -O2 > > CFLAGS_REMOVE_arm-smmu-v3.o := -O2 > > CFLAGS_arm-smmu.o := -O0 > > CFLAGS_arm-smmu-impl.o := -O0 > > CFLAGS_io-pgtable-arm-v7s.o := -O0 > > CFLAGS_io-pgtable-arm.o := -O0 > > CFLAGS_of_iommu.o := -O0 > > CFLAGS_arm-smmu-v3.o := -O0 > > But when I do make ARCH=arm64 CROSS_COMPILE=aarch64-none-elf- Image, I get > > CALL scripts/checksyscalls.sh > > CALL scripts/atomic/check-atomics.sh > > CHK include/generated/compile.h > > CC drivers/iommu/io-pgtable-arm.o > try make drivers/iommu/io-pgtable-arm.i it will show you intermediate output. I did it on kernel/params.i ( wrong config to run yours) you will find the asm goto code therein [jimc@samwise lm-sept]$ less +/jump_label kernel/params.i # 53 "/home/jimc/projects/lx/wk-next/arch/x86/include/asm/jump_label.h" static inline __attribute__((__gnu_inline__)) __attribute__((__unused__)) __attribute__((no_instrument_function)) __attribute__((__always_inline__)) boo l arch_static_branch_jump(struct static_key * const key, const bool branch) { do { asm goto("1:" "jmp %l[l_yes]\n\t" ".pushsection __jump_table, \"aw\" \n\t" " " ".balign 8" " " "\n\t" ".long 1b - . \n\t" ".long %l[l_yes] - . \n \t" " " ".quad" " " "%c0 + %c1 - .\n\t" ".popsection \n\t" : : "i" (key), "i" (branch) : : l_yes); asm (""); } while (0) ; return false; l_yes: return true; } extern int arch_jump_entry_size(struct jump_entry *entry); # 118 "/home/jimc/projects/lx/wk-next/include/linux/jump_label.h" 2 _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
