diff options
| -rw-r--r-- | arch/mips/Kconfig | 30 | ||||
| -rw-r--r-- | arch/mips/include/asm/u-boot-mips.h | 2 | ||||
| -rw-r--r-- | arch/mips/lib/bootm.c | 3 | ||||
| -rw-r--r-- | arch/mips/lib/traps.c | 19 |
4 files changed, 54 insertions, 0 deletions
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index a3ae603..5e20fee 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -287,6 +287,36 @@ config MIPS_RELOCATION_TABLE_SIZE If unsure, leave at the default value. +config RESTORE_EXCEPTION_VECTOR_BASE + bool "Restore exception vector base before booting linux kernel" + default n + help + In U-Boot the exception vector base will be moved to top of memory, + to be used to display register dump when exception occurs. + But some old linux kernel does not honor the base set in CP0_EBASE. + A modified exception vector base will cause kernel crash. + + This option will restore the exception vector base to its previous + value. + + If unsure, say N. + +config OVERRIDE_EXCEPTION_VECTOR_BASE + bool "Override the exception vector base to be restored" + depends on RESTORE_EXCEPTION_VECTOR_BASE + default n + help + Enable this option if you want to use a different exception vector + base rather than the previously saved one. + +config NEW_EXCEPTION_VECTOR_BASE + hex "New exception vector base" + depends on OVERRIDE_EXCEPTION_VECTOR_BASE + range 0x80000000 0xbffff000 + default 0x80000000 + help + The exception vector base to be restored before booting linux kernel + endmenu menu "OS boot interface" diff --git a/arch/mips/include/asm/u-boot-mips.h b/arch/mips/include/asm/u-boot-mips.h index 88438b9..8b37cc4 100644 --- a/arch/mips/include/asm/u-boot-mips.h +++ b/arch/mips/include/asm/u-boot-mips.h @@ -9,4 +9,6 @@ void except_vec_ejtag_debug(void); int arch_misc_init(void); +void trap_restore(void); + #endif /* _U_BOOT_MIPS_H_ */ diff --git a/arch/mips/lib/bootm.c b/arch/mips/lib/bootm.c index 8c0d767..f1db6d2 100644 --- a/arch/mips/lib/bootm.c +++ b/arch/mips/lib/bootm.c @@ -294,6 +294,9 @@ static void boot_jump_linux(bootm_headers_t *images) bootstage_report(); #endif + if (CONFIG_IS_ENABLED(RESTORE_EXCEPTION_VECTOR_BASE)) + trap_restore(); + if (images->ft_len) kernel(-2, (ulong)images->ft_addr, 0, 0); else diff --git a/arch/mips/lib/traps.c b/arch/mips/lib/traps.c index b8568c0..8fff754 100644 --- a/arch/mips/lib/traps.c +++ b/arch/mips/lib/traps.c @@ -20,6 +20,8 @@ DECLARE_GLOBAL_DATA_PTR; +static unsigned long saved_ebase; + static void show_regs(const struct pt_regs *regs) { const int field = 2 * sizeof(unsigned long); @@ -102,7 +104,24 @@ void trap_init(ulong reloc_addr) set_handler(0x180, &except_vec3_generic, 0x80); set_handler(0x280, &except_vec_ejtag_debug, 0x80); + saved_ebase = read_c0_ebase() & 0xfffff000; + write_c0_ebase(ebase); clear_c0_status(ST0_BEV); execution_hazard_barrier(); } + +void trap_restore(void) +{ + set_c0_status(ST0_BEV); + execution_hazard_barrier(); + +#ifdef CONFIG_OVERRIDE_EXCEPTION_VECTOR_BASE + write_c0_ebase(CONFIG_NEW_EXCEPTION_VECTOR_BASE & 0xfffff000); +#else + write_c0_ebase(saved_ebase); +#endif + + clear_c0_status(ST0_BEV); + execution_hazard_barrier(); +} |