diff options
Diffstat (limited to 'arch/x86/kernel/head_32.S')
| -rw-r--r-- | arch/x86/kernel/head_32.S | 113 |
1 files changed, 54 insertions, 59 deletions
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S index 8e7f6556028f..73afd11799ca 100644 --- a/arch/x86/kernel/head_32.S +++ b/arch/x86/kernel/head_32.S @@ -144,6 +144,11 @@ ENTRY(startup_32) movl %eax, pa(olpc_ofw_pgd) #endif +#ifdef CONFIG_MICROCODE_EARLY + /* Early load ucode on BSP. */ + call load_ucode_bsp +#endif + /* * Initialize page tables. This creates a PDE and a set of page * tables, which are located immediately beyond __brk_base. The variable @@ -299,38 +304,59 @@ ENTRY(startup_32_smp) movl %eax,%ss leal -__PAGE_OFFSET(%ecx),%esp +#ifdef CONFIG_MICROCODE_EARLY + /* Early load ucode on AP. */ + call load_ucode_ap +#endif + + default_entry: +#define CR0_STATE (X86_CR0_PE | X86_CR0_MP | X86_CR0_ET | \ + X86_CR0_NE | X86_CR0_WP | X86_CR0_AM | \ + X86_CR0_PG) + movl $(CR0_STATE & ~X86_CR0_PG),%eax + movl %eax,%cr0 + /* - * New page tables may be in 4Mbyte page mode and may - * be using the global pages. + * We want to start out with EFLAGS unambiguously cleared. Some BIOSes leave + * bits like NT set. This would confuse the debugger if this code is traced. So + * initialize them properly now before switching to protected mode. That means + * DF in particular (even though we have cleared it earlier after copying the + * command line) because GCC expects it. + */ + pushl $0 + popfl + +/* + * New page tables may be in 4Mbyte page mode and may be using the global pages. * - * NOTE! If we are on a 486 we may have no cr4 at all! - * Specifically, cr4 exists if and only if CPUID exists - * and has flags other than the FPU flag set. + * NOTE! If we are on a 486 we may have no cr4 at all! Specifically, cr4 exists + * if and only if CPUID exists and has flags other than the FPU flag set. */ + movl $-1,pa(X86_CPUID) # preset CPUID level movl $X86_EFLAGS_ID,%ecx pushl %ecx - popfl - pushfl - popl %eax - pushl $0 - popfl + popfl # set EFLAGS=ID pushfl - popl %edx - xorl %edx,%eax - testl %ecx,%eax - jz 6f # No ID flag = no CPUID = no CR4 + popl %eax # get EFLAGS + testl $X86_EFLAGS_ID,%eax # did EFLAGS.ID remained set? + jz enable_paging # hw disallowed setting of ID bit + # which means no CPUID and no CR4 + + xorl %eax,%eax + cpuid + movl %eax,pa(X86_CPUID) # save largest std CPUID function movl $1,%eax cpuid - andl $~1,%edx # Ignore CPUID.FPU - jz 6f # No flags or only CPUID.FPU = no CR4 + andl $~1,%edx # Ignore CPUID.FPU + jz enable_paging # No flags or only CPUID.FPU = no CR4 movl pa(mmu_cr4_features),%eax movl %eax,%cr4 testb $X86_CR4_PAE, %al # check if PAE is enabled - jz 6f + jz enable_paging /* Check if extended functions are implemented */ movl $0x80000000, %eax @@ -338,7 +364,7 @@ default_entry: /* Value must be in the range 0x80000001 to 0x8000ffff */ subl $0x80000001, %eax cmpl $(0x8000ffff-0x80000001), %eax - ja 6f + ja enable_paging /* Clear bogus XD_DISABLE bits */ call verify_cpu @@ -347,7 +373,7 @@ default_entry: cpuid /* Execute Disable bit supported? */ btl $(X86_FEATURE_NX & 31), %edx - jnc 6f + jnc enable_paging /* Setup EFER (Extended Feature Enable Register) */ movl $MSR_EFER, %ecx @@ -357,15 +383,14 @@ default_entry: /* Make changes effective */ wrmsr -6: +enable_paging: /* * Enable paging */ movl $pa(initial_page_table), %eax movl %eax,%cr3 /* set the page table pointer.. */ - movl %cr0,%eax - orl $X86_CR0_PG,%eax + movl $CR0_STATE,%eax movl %eax,%cr0 /* ..and set paging (PG) bit */ ljmp $__BOOT_CS,$1f /* Clear prefetch and normalize %eip */ 1: @@ -373,14 +398,6 @@ default_entry: addl $__PAGE_OFFSET, %esp /* - * Initialize eflags. Some BIOS's leave bits like NT set. This would - * confuse the debugger if this code is traced. - * XXX - best to initialize before switching to protected mode. - */ - pushl $0 - popfl - -/* * start system 32-bit setup. We need to re-do some of the things done * in 16-bit mode for the "real" operations. */ @@ -389,31 +406,11 @@ default_entry: jz 1f # Did we do this already? call *%eax 1: - -/* check if it is 486 or 386. */ + /* - * XXX - this does a lot of unnecessary setup. Alignment checks don't - * apply at our cpl of 0 and the stack ought to be aligned already, and - * we don't need to preserve eflags. + * Check if it is 486 */ - movl $-1,X86_CPUID # -1 for no CPUID initially - movb $3,X86 # at least 386 - pushfl # push EFLAGS - popl %eax # get EFLAGS - movl %eax,%ecx # save original EFLAGS - xorl $0x240000,%eax # flip AC and ID bits in EFLAGS - pushl %eax # copy to EFLAGS - popfl # set EFLAGS - pushfl # get new EFLAGS - popl %eax # put it in eax - xorl %ecx,%eax # change in flags - pushl %ecx # restore original EFLAGS - popfl - testl $0x40000,%eax # check if AC bit changed - je is386 - - movb $4,X86 # at least 486 - testl $0x200000,%eax # check if ID bit changed + cmpl $-1,X86_CPUID je is486 /* get vendor info */ @@ -439,11 +436,10 @@ default_entry: movb %cl,X86_MASK movl %edx,X86_CAPABILITY -is486: movl $0x50022,%ecx # set AM, WP, NE and MP - jmp 2f - -is386: movl $2,%ecx # set MP -2: movl %cr0,%eax +is486: + movb $4,X86 + movl $0x50022,%ecx # set AM, WP, NE and MP + movl %cr0,%eax andl $0x80000011,%eax # Save PG,PE,ET orl %ecx,%eax movl %eax,%cr0 @@ -468,7 +464,6 @@ is386: movl $2,%ecx # set MP xorl %eax,%eax # Clear LDT lldt %ax - cld # gcc2 wants the direction flag cleared at all times pushl $0 # fake return address for unwinder jmp *(initial_code) |