[PATCH 05/23] x86, realmode: Move SMP trampoline to unified realmode code
From: Jarkko Sakkinen
Date: Tue May 08 2012 - 14:23:19 EST
Migrated SMP trampoline code to the real mode blob.
SMP trampoline code is not yet removed from
.x86_trampoline because it is needed by the wakeup
code.
[ hpa: always enable compiling startup_32_smp in head_32.S... it is
only a few instructions which go into .init on UP builds, and it makes
the rest of the code less #ifdef ugly. ]
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxx>
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
---
arch/x86/include/asm/realmode.h | 18 ++++
arch/x86/kernel/head_32.S | 5 +-
arch/x86/kernel/head_64.S | 4 -
arch/x86/kernel/realmode.c | 14 +++
arch/x86/kernel/smpboot.c | 18 ++--
arch/x86/realmode/rm/Makefile | 1 +
arch/x86/realmode/rm/header.S | 11 +++
arch/x86/realmode/rm/trampoline_32.S | 86 +++++++++++++++++
arch/x86/realmode/rm/trampoline_64.S | 175 ++++++++++++++++++++++++++++++++++
9 files changed, 316 insertions(+), 16 deletions(-)
create mode 100644 arch/x86/realmode/rm/trampoline_32.S
create mode 100644 arch/x86/realmode/rm/trampoline_64.S
diff --git a/arch/x86/include/asm/realmode.h b/arch/x86/include/asm/realmode.h
index bf26b06..9b4a5da 100644
--- a/arch/x86/include/asm/realmode.h
+++ b/arch/x86/include/asm/realmode.h
@@ -13,6 +13,17 @@ struct real_mode_header {
#ifdef CONFIG_X86_32
u32 machine_real_restart_asm;
#endif
+ /* SMP trampoline */
+ u32 trampoline_data;
+ u32 trampoline_status;
+#ifdef CONFIG_X86_32
+ u32 startup_32_smp;
+ u32 boot_gdt;
+#else
+ u32 startup_64_smp;
+ u32 level3_ident_pgt;
+ u32 level3_kernel_pgt;
+#endif
} __attribute__((__packed__));
extern struct real_mode_header real_mode_header;
@@ -25,6 +36,13 @@ extern unsigned long initial_gs;
extern unsigned char real_mode_blob[];
extern unsigned char real_mode_relocs[];
+#ifdef CONFIG_X86_32
+extern unsigned char startup_32_smp[];
+extern unsigned char boot_gdt[];
+#else
+extern unsigned char secondary_startup_64[];
+#endif
+
extern void __init setup_real_mode(void);
#endif /* _ARCH_X86_REALMODE_H */
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index ce0be7c..a3c2b4f 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -273,10 +273,7 @@ num_subarch_entries = (. - subarch_entries) / 4
* If cpu hotplug is not supported then this code can go in init section
* which will be freed later
*/
-
__CPUINIT
-
-#ifdef CONFIG_SMP
ENTRY(startup_32_smp)
cld
movl $(__BOOT_DS),%eax
@@ -287,7 +284,7 @@ ENTRY(startup_32_smp)
movl pa(stack_start),%ecx
movl %eax,%ss
leal -__PAGE_OFFSET(%ecx),%esp
-#endif /* CONFIG_SMP */
+
default_entry:
/*
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 40f4eb3..d70bc2e 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -136,10 +136,6 @@ ident_complete:
/* Fixup phys_base */
addq %rbp, phys_base(%rip)
- /* Fixup trampoline */
- addq %rbp, trampoline_level4_pgt + 0(%rip)
- addq %rbp, trampoline_level4_pgt + (511*8)(%rip)
-
/* Due to ENTRY(), sometimes the empty space gets filled with
* zeros. Better take a jmp than relying on empty space being
* filled with 0x90 (nop)
diff --git a/arch/x86/kernel/realmode.c b/arch/x86/kernel/realmode.c
index 7415c42..a465775 100644
--- a/arch/x86/kernel/realmode.c
+++ b/arch/x86/kernel/realmode.c
@@ -58,6 +58,20 @@ void __init setup_real_mode(void)
/* Copied header will contain relocated physical addresses. */
memcpy(&real_mode_header, real_mode_base,
sizeof(struct real_mode_header));
+
+#ifdef CONFIG_X86_32
+ *((u32 *)__va(real_mode_header.startup_32_smp)) = __pa(startup_32_smp);
+ *((u32 *)__va(real_mode_header.boot_gdt)) = __pa(boot_gdt);
+#else
+ *((u64 *) __va(real_mode_header.startup_64_smp)) =
+ (u64) __pa(secondary_startup_64);
+
+ *((u64 *) __va(real_mode_header.level3_ident_pgt)) =
+ __pa(level3_ident_pgt) + _KERNPG_TABLE;
+
+ *((u64 *) __va(real_mode_header.level3_kernel_pgt)) =
+ __pa(level3_kernel_pgt) + _KERNPG_TABLE;
+#endif
}
/*
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 6e1e406..c7971ea 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -57,7 +57,7 @@
#include <asm/nmi.h>
#include <asm/irq.h>
#include <asm/idle.h>
-#include <asm/trampoline.h>
+#include <asm/realmode.h>
#include <asm/cpu.h>
#include <asm/numa.h>
#include <asm/pgtable.h>
@@ -73,6 +73,8 @@
#include <asm/smpboot_hooks.h>
#include <asm/i8259.h>
+#include <asm/realmode.h>
+
/* State of each CPU */
DEFINE_PER_CPU(int, cpu_state) = { 0 };
@@ -662,8 +664,12 @@ static void __cpuinit announce_cpu(int cpu, int apicid)
*/
static int __cpuinit do_boot_cpu(int apicid, int cpu)
{
+ volatile u32 *trampoline_status =
+ (volatile u32 *) __va(real_mode_header.trampoline_status);
+ /* start_ip had better be page-aligned! */
+ unsigned long start_ip = real_mode_header.trampoline_data;
+
unsigned long boot_error = 0;
- unsigned long start_ip;
int timeout;
struct create_idle c_idle = {
.cpu = cpu,
@@ -713,9 +719,6 @@ do_rest:
initial_code = (unsigned long)start_secondary;
stack_start = c_idle.idle->thread.sp;
- /* start_ip had better be page-aligned! */
- start_ip = trampoline_address();
-
/* So we see what's up */
announce_cpu(cpu, apicid);
@@ -778,8 +781,7 @@ do_rest:
pr_debug("CPU%d: has booted.\n", cpu);
} else {
boot_error = 1;
- if (*(volatile u32 *)TRAMPOLINE_SYM(trampoline_status)
- == 0xA5A5A5A5)
+ if (*trampoline_status == 0xA5A5A5A5)
/* trampoline started but...? */
pr_err("CPU%d: Stuck ??\n", cpu);
else
@@ -805,7 +807,7 @@ do_rest:
}
/* mark "stuck" area as not stuck */
- *(volatile u32 *)TRAMPOLINE_SYM(trampoline_status) = 0;
+ *trampoline_status = 0;
if (get_uv_system_type() != UV_NON_UNIQUE_APIC) {
/*
diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile
index 3f851c4..56ec64f 100644
--- a/arch/x86/realmode/rm/Makefile
+++ b/arch/x86/realmode/rm/Makefile
@@ -13,6 +13,7 @@ always := realmode.bin
realmode-y += header.o
realmode-$(CONFIG_X86_32) += reboot_32.o
+realmode-y += trampoline_$(BITS).o
targets += $(realmode-y)
diff --git a/arch/x86/realmode/rm/header.S b/arch/x86/realmode/rm/header.S
index db21401..a979004 100644
--- a/arch/x86/realmode/rm/header.S
+++ b/arch/x86/realmode/rm/header.S
@@ -16,4 +16,15 @@ ENTRY(real_mode_header)
#ifdef CONFIG_X86_32
.long pa_machine_real_restart_asm
#endif
+ /* SMP trampoline */
+ .long pa_trampoline_data
+ .long pa_trampoline_status
+#ifdef CONFIG_X86_32
+ .long pa_startup_32_smp
+ .long pa_boot_gdt
+#else
+ .long pa_startup_64_smp
+ .long pa_level3_ident_pgt
+ .long pa_level3_kernel_pgt
+#endif
END(real_mode_header)
diff --git a/arch/x86/realmode/rm/trampoline_32.S b/arch/x86/realmode/rm/trampoline_32.S
new file mode 100644
index 0000000..18cb7fc
--- /dev/null
+++ b/arch/x86/realmode/rm/trampoline_32.S
@@ -0,0 +1,86 @@
+/*
+ *
+ * Trampoline.S Derived from Setup.S by Linus Torvalds
+ *
+ * 4 Jan 1997 Michael Chastain: changed to gnu as.
+ *
+ * This is only used for booting secondary CPUs in SMP machine
+ *
+ * Entry: CS:IP point to the start of our code, we are
+ * in real mode with no stack, but the rest of the
+ * trampoline page to make our stack and everything else
+ * is a mystery.
+ *
+ * We jump into arch/x86/kernel/head_32.S.
+ *
+ * On entry to trampoline_data, the processor is in real mode
+ * with 16-bit addressing and 16-bit data. CS has some value
+ * and IP is zero. Thus, we load CS to the physical segment
+ * of the real mode code before doing anything further.
+ *
+ * The structure real_mode_header includes entries that need
+ * to be set up before executing this code:
+ *
+ * startup_32_smp
+ * boot_gdt
+ */
+
+#include <linux/linkage.h>
+#include <linux/init.h>
+#include <asm/segment.h>
+#include <asm/page_types.h>
+
+ .text
+ .code16
+ .globl trampoline_data
+
+ .balign PAGE_SIZE
+trampoline_data:
+ wbinvd # Needed for NUMA-Q should be harmless for others
+
+ .byte 0xea # ljmpw
+ .word 1f # Offset
+ .word real_mode_seg # Segment
+1:
+ mov %cs, %ax # Code and data in the same place
+ mov %ax, %ds
+
+ cli # We should be safe anyway
+
+ movl $0xA5A5A5A5, trampoline_status
+ # write marker for master knows we're running
+
+ /* GDT tables in non default location kernel can be beyond 16MB and
+ * lgdt will not be able to load the address as in real mode default
+ * operand size is 16bit. Use lgdtl instead to force operand size
+ * to 32 bit.
+ */
+
+ lidtl boot_idt_descr # load idt with 0, 0
+ lgdtl boot_gdt_descr # load gdt with whatever is appropriate
+
+ xor %ax, %ax
+ inc %ax # protected mode (PE) bit
+ lmsw %ax # into protected mode
+
+ # flush prefetch and jump to startup_32_smp in arch/i386/kernel/head.S
+ ljmpl *(startup_32_smp)
+
+ .data
+ .globl startup_32_smp, boot_gdt, trampoline_status
+
+boot_gdt_descr:
+ .word __BOOT_DS + 7 # gdt limit
+boot_gdt:
+ .long 0 # gdt base
+
+boot_idt_descr:
+ .word 0 # idt limit = 0
+ .long 0 # idt base = 0L
+
+trampoline_status:
+ .long 0
+
+startup_32_smp:
+ .long 0x00000000
+ .word __BOOT_CS, 0
diff --git a/arch/x86/realmode/rm/trampoline_64.S b/arch/x86/realmode/rm/trampoline_64.S
new file mode 100644
index 0000000..063da00
--- /dev/null
+++ b/arch/x86/realmode/rm/trampoline_64.S
@@ -0,0 +1,175 @@
+/*
+ *
+ * Trampoline.S Derived from Setup.S by Linus Torvalds
+ *
+ * 4 Jan 1997 Michael Chastain: changed to gnu as.
+ * 15 Sept 2005 Eric Biederman: 64bit PIC support
+ *
+ * Entry: CS:IP point to the start of our code, we are
+ * in real mode with no stack, but the rest of the
+ * trampoline page to make our stack and everything else
+ * is a mystery.
+ *
+ * On entry to trampoline_data, the processor is in real mode
+ * with 16-bit addressing and 16-bit data. CS has some value
+ * and IP is zero. Thus, data addresses need to be absolute
+ * (no relocation) and are taken with regard to r_base.
+ *
+ * With the addition of trampoline_level4_pgt this code can
+ * now enter a 64bit kernel that lives at arbitrary 64bit
+ * physical addresses.
+ *
+ * If you work on this file, check the object module with objdump
+ * --full-contents --reloc to make sure there are no relocation
+ * entries.
+ */
+
+#include <linux/linkage.h>
+#include <linux/init.h>
+#include <asm/pgtable_types.h>
+#include <asm/page_types.h>
+#include <asm/msr.h>
+#include <asm/segment.h>
+#include <asm/processor-flags.h>
+
+ .text
+ .balign PAGE_SIZE
+ .code16
+
+ENTRY(trampoline_data)
+ cli # We should be safe anyway
+ wbinvd
+
+ .byte 0xea # ljmpw
+ .word 1f # Offset
+ .word real_mode_seg # Segment
+1:
+ mov %cs, %ax # Code and data in the same place
+ mov %ax, %ds
+ mov %ax, %es
+ mov %ax, %ss
+
+ movl $0xA5A5A5A5, trampoline_status
+ # write marker for master knows we're running
+
+ # Setup stack
+ movw $trampoline_stack_end, %sp
+
+ call verify_cpu # Verify the cpu supports long mode
+ testl %eax, %eax # Check for return code
+ jnz no_longmode
+
+ /*
+ * GDT tables in non default location kernel can be beyond 16MB and
+ * lgdt will not be able to load the address as in real mode default
+ * operand size is 16bit. Use lgdtl instead to force operand size
+ * to 32 bit.
+ */
+
+ lidtl tidt # load idt with 0, 0
+ lgdtl tgdt # load gdt with whatever is appropriate
+
+ mov $X86_CR0_PE, %ax # protected mode (PE) bit
+ lmsw %ax # into protected mode
+
+ # flush prefetch and jump to startup_32
+ ljmpl *(startup_32_vector)
+
+no_longmode:
+ hlt
+ jmp no_longmode
+#include "../kernel/verify_cpu.S"
+
+ .code32
+ .balign 4
+ENTRY(startup_32)
+ movl $__KERNEL_DS, %eax # Initialize the %ds segment register
+ movl %eax, %ds
+
+ movl $X86_CR4_PAE, %eax
+ movl %eax, %cr4 # Enable PAE mode
+
+ movl pa_startup_64_smp, %esi
+ movl pa_startup_64_smp_high, %edi
+
+ # Setup trampoline 4 level pagetables
+ leal pa_trampoline_level4_pgt, %eax
+ movl %eax, %cr3
+
+ movl $MSR_EFER, %ecx
+ movl $(1 << _EFER_LME), %eax # Enable Long Mode
+ xorl %edx, %edx
+ wrmsr
+
+ # Enable paging and in turn activate Long Mode
+ # Enable protected mode
+ movl $(X86_CR0_PG | X86_CR0_PE), %eax
+ movl %eax, %cr0
+
+ /*
+ * At this point we're in long mode but in 32bit compatibility mode
+ * with EFER.LME = 1, CS.L = 0, CS.D = 1 (and in turn
+ * EFER.LMA = 1). Now we want to jump in 64bit mode, to do that we use
+ * the new gdt/idt that has __KERNEL_CS with CS.L = 1.
+ */
+ ljmpl *(pa_startup_64_vector)
+
+ .code64
+ .balign 4
+ENTRY(startup_64)
+ # Now jump into the kernel using virtual addresses
+ movl %edi, %eax
+ shlq $32, %rax
+ addl %esi, %eax
+ jmp *%rax
+
+ # Careful these need to be in the same 64K segment as the above;
+tidt:
+ .word 0 # idt limit = 0
+ .word 0, 0 # idt base = 0L
+
+ # Duplicate the global descriptor table
+ # so the kernel can live anywhere
+ .balign 4
+ .globl tgdt
+tgdt:
+ .short tgdt_end - tgdt # gdt limit
+ .long pa_tgdt
+ .short 0
+ .quad 0x00cf9b000000ffff # __KERNEL32_CS
+ .quad 0x00af9b000000ffff # __KERNEL_CS
+ .quad 0x00cf93000000ffff # __KERNEL_DS
+tgdt_end:
+
+ .balign 4
+startup_32_vector:
+ .long pa_startup_32
+ .word __KERNEL32_CS, 0
+
+ .balign 4
+ .globl startup_64_vector
+startup_64_vector:
+ .long pa_startup_64
+ .word __KERNEL_CS, 0
+
+ .data
+
+ .balign 4
+ENTRY(trampoline_status)
+ .long 0
+
+trampoline_stack:
+ .org 0x1000
+trampoline_stack_end:
+
+ .globl level3_ident_pgt
+ .globl level3_kernel_pgt
+ENTRY(trampoline_level4_pgt)
+ level3_ident_pgt: .quad 0
+ .fill 510,8,0
+ level3_kernel_pgt: .quad 0
+
+ .globl startup_64_smp
+ .globl startup_64_smp_high
+startup_64_smp: .long 0
+startup_64_smp_high: .long 0
--
1.7.9.5
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