Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit cda846f1 authored by Jarkko Sakkinen's avatar Jarkko Sakkinen Committed by H. Peter Anvin
Browse files

x86, realmode: read cr4 and EFER from kernel for 64-bit trampoline 



This patch changes 64-bit trampoline so that CR4 and
EFER are provided by the kernel instead of using fixed
values.

Signed-off-by: default avatarJarkko Sakkinen <jarkko.sakkinen@intel.com>
Link: http://lkml.kernel.org/r/1336501366-28617-24-git-send-email-jarkko.sakkinen@intel.com


Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent bf8b88e9

arch/x86/include/asm/processor.h

+6 −1
Original line number Diff line number Diff line
@@ -545,12 +545,15 @@ static inline void load_sp0(struct tss_struct *tss, 
 * after us can get the correct flags.

 */

extern unsigned long mmu_cr4_features;

extern u32 *trampoline_cr4_features;



static inline void set_in_cr4(unsigned long mask)

{

	unsigned long cr4;



	mmu_cr4_features |= mask;

	if (trampoline_cr4_features)

		*trampoline_cr4_features = mmu_cr4_features;

	cr4 = read_cr4();

	cr4 |= mask;

	write_cr4(cr4);
@@ -561,6 +564,8 @@ static inline void clear_in_cr4(unsigned long mask) 
	unsigned long cr4;



	mmu_cr4_features &= ~mask;

	if (trampoline_cr4_features)

		*trampoline_cr4_features = mmu_cr4_features;

	cr4 = read_cr4();

	cr4 &= ~mask;

	write_cr4(cr4);

arch/x86/include/asm/realmode.h

+6 −2
Original line number Diff line number Diff line
@@ -24,18 +24,22 @@ struct real_mode_header { 
#ifdef CONFIG_X86_32

	u32	machine_real_restart_asm;

#endif

} __attribute__((__packed__));

};



/* This must match data at trampoline_32/64.S */

struct trampoline_header {

#ifdef CONFIG_X86_32

	u32 start;

	u16 gdt_pad;

	u16 gdt_limit;

	u32 gdt_base;

#else

	u64 start;

	u32 cr4;

	u32 efer_low;

	u32 efer_high;

#endif

} __attribute__((__packed__));

};



extern struct real_mode_header *real_mode_header;

extern unsigned char real_mode_blob_end[];

arch/x86/kernel/realmode.c

+8 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
#include <asm/realmode.h>



struct real_mode_header *real_mode_header;

u32 *trampoline_cr4_features;



void __init setup_real_mode(void)

{
@@ -64,7 +65,14 @@ void __init setup_real_mode(void) 
	trampoline_header->gdt_limit = __BOOT_DS + 7;

	trampoline_header->gdt_base = __pa(boot_gdt);

#else

	if (rdmsr_safe(MSR_EFER, &trampoline_header->efer_low,

		       &trampoline_header->efer_high))

		BUG();



	trampoline_header->start = (u64) secondary_startup_64;

	trampoline_cr4_features = &trampoline_header->cr4;

	*trampoline_cr4_features = read_cr4();



	trampoline_pgd = (u64 *) __va(real_mode_header->trampoline_pgd);

	trampoline_pgd[0] = __pa(level3_ident_pgt) + _KERNPG_TABLE;

	trampoline_pgd[511] = __pa(level3_kernel_pgt) + _KERNPG_TABLE;

arch/x86/kernel/setup.c

+2 −0
Original line number Diff line number Diff line
@@ -975,6 +975,8 @@ void __init setup_arch(char **cmdline_p) 
	if (boot_cpu_data.cpuid_level >= 0) {

		/* A CPU has %cr4 if and only if it has CPUID */

		mmu_cr4_features = read_cr4();

		if (trampoline_cr4_features)

			*trampoline_cr4_features = mmu_cr4_features;

	}



#ifdef CONFIG_X86_32

arch/x86/realmode/rm/header.S

+1 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 


	.section ".header", "a"



	.balign	16

GLOBAL(real_mode_header)

	.long	pa_text_start

	.long	pa_ro_end