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Diffstat (limited to 'arch/xtensa/Kconfig')
| -rw-r--r-- | arch/xtensa/Kconfig | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig index b09de49dbec..213ac3d9f95 100644 --- a/arch/xtensa/Kconfig +++ b/arch/xtensa/Kconfig @@ -103,6 +103,35 @@ config MATH_EMULATION help Can we use information of configuration file? +config INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX + bool "Initialize Xtensa MMU inside the Linux kernel code" + default y + help + Earlier version initialized the MMU in the exception vector + before jumping to _startup in head.S and had an advantage that + it was possible to place a software breakpoint at 'reset' and + then enter your normal kernel breakpoints once the MMU was mapped + to the kernel mappings (0XC0000000). + + This unfortunately doesn't work for U-Boot and likley also wont + work for using KEXEC to have a hot kernel ready for doing a + KDUMP. + + So now the MMU is initialized in head.S but it's necessary to + use hardware breakpoints (gdb 'hbreak' cmd) to break at _startup. + xt-gdb can't place a Software Breakpoint in the 0XD region prior + to mapping the MMU and after mapping even if the area of low memory + was mapped gdb wouldn't remove the breakpoint on hitting it as the + PC wouldn't match. Since Hardware Breakpoints are recommended for + Linux configurations it seems reasonable to just assume they exist + and leave this older mechanism for unfortunate souls that choose + not to follow Tensilica's recommendation. + + Selecting this will cause U-Boot to set the KERNEL Load and Entry + address at 0x00003000 instead of the mapped std of 0xD0003000. + + If in doubt, say Y. + endmenu config XTENSA_CALIBRATE_CCOUNT |