diff options
Diffstat (limited to 'arch/xtensa/kernel/head.S')
| -rw-r--r-- | arch/xtensa/kernel/head.S | 130 |
1 files changed, 87 insertions, 43 deletions
diff --git a/arch/xtensa/kernel/head.S b/arch/xtensa/kernel/head.S index 7d740ebbe198..74ec62c892bc 100644 --- a/arch/xtensa/kernel/head.S +++ b/arch/xtensa/kernel/head.S @@ -19,6 +19,7 @@ #include <asm/page.h> #include <asm/cacheasm.h> #include <asm/initialize_mmu.h> +#include <asm/mxregs.h> #include <linux/init.h> #include <linux/linkage.h> @@ -54,7 +55,7 @@ ENTRY(_start) /* Preserve the pointer to the boot parameter list in EXCSAVE_1 */ wsr a2, excsave1 - _j _SetupMMU + _j _SetupOCD .align 4 .literal_position @@ -62,6 +63,23 @@ ENTRY(_start) .word _startup .align 4 +_SetupOCD: + /* + * Initialize WB, WS, and clear PS.EXCM (to allow loop instructions). + * Set Interrupt Level just below XCHAL_DEBUGLEVEL to allow + * xt-gdb to single step via DEBUG exceptions received directly + * by ocd. + */ + movi a1, 1 + movi a0, 0 + wsr a1, windowstart + wsr a0, windowbase + rsync + + movi a1, LOCKLEVEL + wsr a1, ps + rsync + .global _SetupMMU _SetupMMU: Offset = _SetupMMU - _start @@ -90,19 +108,6 @@ ENDPROC(_start) ENTRY(_startup) - /* Disable interrupts and exceptions. */ - - movi a0, LOCKLEVEL - wsr a0, ps - - /* Start with a fresh windowbase and windowstart. */ - - movi a1, 1 - movi a0, 0 - wsr a1, windowstart - wsr a0, windowbase - rsync - /* Set a0 to 0 for the remaining initialization. */ movi a0, 0 @@ -154,17 +159,6 @@ ENTRY(_startup) wsr a0, cpenable #endif - /* Set PS.INTLEVEL=LOCKLEVEL, PS.WOE=0, kernel stack, PS.EXCM=0 - * - * Note: PS.EXCM must be cleared before using any loop - * instructions; otherwise, they are silently disabled, and - * at most one iteration of the loop is executed. - */ - - movi a1, LOCKLEVEL - wsr a1, ps - rsync - /* Initialize the caches. * a2, a3 are just working registers (clobbered). */ @@ -182,6 +176,37 @@ ENTRY(_startup) isync +#ifdef CONFIG_HAVE_SMP + movi a2, CCON # MX External Register to Configure Cache + movi a3, 1 + wer a3, a2 +#endif + + /* Setup stack and enable window exceptions (keep irqs disabled) */ + + movi a1, start_info + l32i a1, a1, 0 + + movi a2, (1 << PS_WOE_BIT) | LOCKLEVEL + # WOE=1, INTLEVEL=LOCKLEVEL, UM=0 + wsr a2, ps # (enable reg-windows; progmode stack) + rsync + + /* Set up EXCSAVE[DEBUGLEVEL] to point to the Debug Exception Handler.*/ + + movi a2, debug_exception + wsr a2, SREG_EXCSAVE + XCHAL_DEBUGLEVEL + +#ifdef CONFIG_SMP + /* + * Notice that we assume with SMP that cores have PRID + * supported by the cores. + */ + rsr a2, prid + bnez a2, .Lboot_secondary + +#endif /* CONFIG_SMP */ + /* Unpack data sections * * The linker script used to build the Linux kernel image @@ -234,24 +259,7 @@ ENTRY(_startup) ___invalidate_icache_all a2 a3 isync - /* Setup stack and enable window exceptions (keep irqs disabled) */ - - movi a1, init_thread_union - addi a1, a1, KERNEL_STACK_SIZE - - movi a2, (1 << PS_WOE_BIT) | LOCKLEVEL - # WOE=1, INTLEVEL=LOCKLEVEL, UM=0 - wsr a2, ps # (enable reg-windows; progmode stack) - rsync - - /* Set up EXCSAVE[DEBUGLEVEL] to point to the Debug Exception Handler.*/ - - movi a2, debug_exception - wsr a2, SREG_EXCSAVE + XCHAL_DEBUGLEVEL - - /* Set up EXCSAVE[1] to point to the exc_table. */ - - movi a6, exc_table + movi a6, 0 xsr a6, excsave1 /* init_arch kick-starts the linux kernel */ @@ -265,9 +273,45 @@ ENTRY(_startup) should_never_return: j should_never_return +#ifdef CONFIG_SMP +.Lboot_secondary: + + movi a2, cpu_start_ccount +1: + l32i a3, a2, 0 + beqi a3, 0, 1b + movi a3, 0 + s32i a3, a2, 0 + memw +1: + l32i a3, a2, 0 + beqi a3, 0, 1b + wsr a3, ccount + movi a3, 0 + s32i a3, a2, 0 + memw + + movi a6, 0 + wsr a6, excsave1 + + movi a4, secondary_start_kernel + callx4 a4 + j should_never_return + +#endif /* CONFIG_SMP */ + ENDPROC(_startup) /* + * DATA section + */ + + .section ".data.init.refok" + .align 4 +ENTRY(start_info) + .long init_thread_union + KERNEL_STACK_SIZE + +/* * BSS section */ |