diff options
Diffstat (limited to 'arch/sparc64/kernel/head.S')
| -rw-r--r-- | arch/sparc64/kernel/head.S | 61 |
1 files changed, 26 insertions, 35 deletions
diff --git a/arch/sparc64/kernel/head.S b/arch/sparc64/kernel/head.S index 4c942f7..b49dcd4 100644 --- a/arch/sparc64/kernel/head.S +++ b/arch/sparc64/kernel/head.S @@ -28,19 +28,14 @@ #include <asm/mmu.h> /* This section from from _start to sparc64_boot_end should fit into - * 0x0000.0000.0040.4000 to 0x0000.0000.0040.8000 and will be sharing space - * with bootup_user_stack, which is from 0x0000.0000.0040.4000 to - * 0x0000.0000.0040.6000 and empty_bad_page, which is from - * 0x0000.0000.0040.6000 to 0x0000.0000.0040.8000. + * 0x0000000000404000 to 0x0000000000408000. */ - .text .globl start, _start, stext, _stext _start: start: _stext: stext: -bootup_user_stack: ! 0x0000000000404000 b sparc64_boot flushw /* Flush register file. */ @@ -392,31 +387,30 @@ tlb_fixup_done: * former does use this code, the latter does not yet due * to some complexities. That should be fixed up at some * point. + * + * There used to be enormous complexity wrt. transferring + * over from the firwmare's trap table to the Linux kernel's. + * For example, there was a chicken & egg problem wrt. building + * the OBP page tables, yet needing to be on the Linux kernel + * trap table (to translate PAGE_OFFSET addresses) in order to + * do that. + * + * We now handle OBP tlb misses differently, via linear lookups + * into the prom_trans[] array. So that specific problem no + * longer exists. Yet, unfortunately there are still some issues + * preventing trampoline.S from using this code... ho hum. */ .globl setup_trap_table setup_trap_table: save %sp, -192, %sp - /* Force interrupts to be disabled. Transferring over to - * the Linux trap table is a very delicate operation. - * Until we are actually on the Linux trap table, we cannot - * get the PAGE_OFFSET linear mappings translated. We need - * that mapping to be setup in order to initialize the firmware - * page tables. - * - * So there is this window of time, from the return from - * prom_set_trap_table() until inherit_prom_mappings_post() - * (in arch/sparc64/mm/init.c) completes, during which no - * firmware address space accesses can be made. - */ + /* Force interrupts to be disabled. */ rdpr %pstate, %o1 andn %o1, PSTATE_IE, %o1 wrpr %o1, 0x0, %pstate wrpr %g0, 15, %pil - /* Ok, now make the final valid firmware call to jump over - * to the Linux trap table. - */ + /* Make the firmware call to jump over to the Linux trap table. */ call prom_set_trap_table sethi %hi(sparc64_ttable_tl0), %o0 @@ -540,15 +534,21 @@ setup_tba: /* i0 = is_starfire */ ret restore +sparc64_boot_end: + +#include "systbls.S" +#include "ktlb.S" +#include "etrap.S" +#include "rtrap.S" +#include "winfixup.S" +#include "entry.S" /* - * The following skips make sure the trap table in ttable.S is aligned + * The following skip makes sure the trap table in ttable.S is aligned * on a 32K boundary as required by the v9 specs for TBA register. */ -sparc64_boot_end: - .skip 0x2000 + _start - sparc64_boot_end -bootup_user_stack_end: - .skip 0x2000 +1: + .skip 0x4000 + _start - 1b #ifdef CONFIG_SBUS /* This is just a hack to fool make depend config.h discovering @@ -560,15 +560,6 @@ bootup_user_stack_end: ! 0x0000000000408000 #include "ttable.S" -#include "systbls.S" -#include "ktlb.S" -#include "etrap.S" -#include "rtrap.S" -#include "winfixup.S" -#include "entry.S" - - /* This is just anal retentiveness on my part... */ - .align 16384 .data .align 8 |