Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 623 insertions, 0 deletions

diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
new file mode 100644
index 000000000..30f9cb2c0
--- /dev/null
+++ b/arch/x86/kernel/head_32.S
@@ -0,0 +1,623 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  Enhanced CPU detection and feature setting code by Mike Jagdis
+ *  and Martin Mares, November 1997.
+ */
+
+.text
+#include <linux/threads.h>
+#include <linux/init.h>
+#include <linux/linkage.h>
+#include <asm/segment.h>
+#include <asm/page_types.h>
+#include <asm/pgtable_types.h>
+#include <asm/cache.h>
+#include <asm/thread_info.h>
+#include <asm/asm-offsets.h>
+#include <asm/setup.h>
+#include <asm/processor-flags.h>
+#include <asm/msr-index.h>
+#include <asm/cpufeatures.h>
+#include <asm/percpu.h>
+#include <asm/nops.h>
+#include <asm/bootparam.h>
+#include <asm/export.h>
+#include <asm/pgtable_32.h>
+
+/* Physical address */
+#define pa(X) ((X) - __PAGE_OFFSET)
+
+/*
+ * References to members of the new_cpu_data structure.
+ */
+
+#define X86		new_cpu_data+CPUINFO_x86
+#define X86_VENDOR	new_cpu_data+CPUINFO_x86_vendor
+#define X86_MODEL	new_cpu_data+CPUINFO_x86_model
+#define X86_STEPPING	new_cpu_data+CPUINFO_x86_stepping
+#define X86_HARD_MATH	new_cpu_data+CPUINFO_hard_math
+#define X86_CPUID	new_cpu_data+CPUINFO_cpuid_level
+#define X86_CAPABILITY	new_cpu_data+CPUINFO_x86_capability
+#define X86_VENDOR_ID	new_cpu_data+CPUINFO_x86_vendor_id
+
+
+#define SIZEOF_PTREGS 17*4
+
+/*
+ * Worst-case size of the kernel mapping we need to make:
+ * a relocatable kernel can live anywhere in lowmem, so we need to be able
+ * to map all of lowmem.
+ */
+KERNEL_PAGES = LOWMEM_PAGES
+
+INIT_MAP_SIZE = PAGE_TABLE_SIZE(KERNEL_PAGES) * PAGE_SIZE
+RESERVE_BRK(pagetables, INIT_MAP_SIZE)
+
+/*
+ * 32-bit kernel entrypoint; only used by the boot CPU.  On entry,
+ * %esi points to the real-mode code as a 32-bit pointer.
+ * CS and DS must be 4 GB flat segments, but we don't depend on
+ * any particular GDT layout, because we load our own as soon as we
+ * can.
+ */
+__HEAD
+ENTRY(startup_32)
+	movl pa(initial_stack),%ecx
+	
+	/* test KEEP_SEGMENTS flag to see if the bootloader is asking
+		us to not reload segments */
+	testb $KEEP_SEGMENTS, BP_loadflags(%esi)
+	jnz 2f
+
+/*
+ * Set segments to known values.
+ */
+	lgdt pa(boot_gdt_descr)
+	movl $(__BOOT_DS),%eax
+	movl %eax,%ds
+	movl %eax,%es
+	movl %eax,%fs
+	movl %eax,%gs
+	movl %eax,%ss
+2:
+	leal -__PAGE_OFFSET(%ecx),%esp
+
+/*
+ * Clear BSS first so that there are no surprises...
+ */
+	cld
+	xorl %eax,%eax
+	movl $pa(__bss_start),%edi
+	movl $pa(__bss_stop),%ecx
+	subl %edi,%ecx
+	shrl $2,%ecx
+	rep ; stosl
+/*
+ * Copy bootup parameters out of the way.
+ * Note: %esi still has the pointer to the real-mode data.
+ * With the kexec as boot loader, parameter segment might be loaded beyond
+ * kernel image and might not even be addressable by early boot page tables.
+ * (kexec on panic case). Hence copy out the parameters before initializing
+ * page tables.
+ */
+	movl $pa(boot_params),%edi
+	movl $(PARAM_SIZE/4),%ecx
+	cld
+	rep
+	movsl
+	movl pa(boot_params) + NEW_CL_POINTER,%esi
+	andl %esi,%esi
+	jz 1f			# No command line
+	movl $pa(boot_command_line),%edi
+	movl $(COMMAND_LINE_SIZE/4),%ecx
+	rep
+	movsl
+1:
+
+#ifdef CONFIG_OLPC
+	/* save OFW's pgdir table for later use when calling into OFW */
+	movl %cr3, %eax
+	movl %eax, pa(olpc_ofw_pgd)
+#endif
+
+#ifdef CONFIG_MICROCODE
+	/* Early load ucode on BSP. */
+	call load_ucode_bsp
+#endif
+
+	/* Create early pagetables. */
+	call  mk_early_pgtbl_32
+
+	/* Do early initialization of the fixmap area */
+	movl $pa(initial_pg_fixmap)+PDE_IDENT_ATTR,%eax
+#ifdef  CONFIG_X86_PAE
+#define KPMDS (((-__PAGE_OFFSET) >> 30) & 3) /* Number of kernel PMDs */
+	movl %eax,pa(initial_pg_pmd+0x1000*KPMDS-8)
+#else
+	movl %eax,pa(initial_page_table+0xffc)
+#endif
+
+#ifdef CONFIG_PARAVIRT
+	/* This is can only trip for a broken bootloader... */
+	cmpw $0x207, pa(boot_params + BP_version)
+	jb .Ldefault_entry
+
+	/* Paravirt-compatible boot parameters.  Look to see what architecture
+		we're booting under. */
+	movl pa(boot_params + BP_hardware_subarch), %eax
+	cmpl $num_subarch_entries, %eax
+	jae .Lbad_subarch
+
+	movl pa(subarch_entries)(,%eax,4), %eax
+	subl $__PAGE_OFFSET, %eax
+	jmp *%eax
+
+.Lbad_subarch:
+WEAK(xen_entry)
+	/* Unknown implementation; there's really
+	   nothing we can do at this point. */
+	ud2a
+
+	__INITDATA
+
+subarch_entries:
+	.long .Ldefault_entry		/* normal x86/PC */
+	.long xen_entry			/* Xen hypervisor */
+	.long .Ldefault_entry		/* Moorestown MID */
+num_subarch_entries = (. - subarch_entries) / 4
+.previous
+#else
+	jmp .Ldefault_entry
+#endif /* CONFIG_PARAVIRT */
+
+#ifdef CONFIG_HOTPLUG_CPU
+/*
+ * Boot CPU0 entry point. It's called from play_dead(). Everything has been set
+ * up already except stack. We just set up stack here. Then call
+ * start_secondary().
+ */
+ENTRY(start_cpu0)
+	movl initial_stack, %ecx
+	movl %ecx, %esp
+	call *(initial_code)
+1:	jmp 1b
+ENDPROC(start_cpu0)
+#endif
+
+/*
+ * Non-boot CPU entry point; entered from trampoline.S
+ * We can't lgdt here, because lgdt itself uses a data segment, but
+ * we know the trampoline has already loaded the boot_gdt for us.
+ *
+ * If cpu hotplug is not supported then this code can go in init section
+ * which will be freed later
+ */
+ENTRY(startup_32_smp)
+	cld
+	movl $(__BOOT_DS),%eax
+	movl %eax,%ds
+	movl %eax,%es
+	movl %eax,%fs
+	movl %eax,%gs
+	movl pa(initial_stack),%ecx
+	movl %eax,%ss
+	leal -__PAGE_OFFSET(%ecx),%esp
+
+#ifdef CONFIG_MICROCODE
+	/* Early load ucode on AP. */
+	call load_ucode_ap
+#endif
+
+.Ldefault_entry:
+	movl $(CR0_STATE & ~X86_CR0_PG),%eax
+	movl %eax,%cr0
+
+/*
+ * 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.
+ */
+	movl $-1,pa(X86_CPUID)		# preset CPUID level
+	movl $X86_EFLAGS_ID,%ecx
+	pushl %ecx
+	popfl				# set EFLAGS=ID
+	pushfl
+	popl %eax			# get EFLAGS
+	testl $X86_EFLAGS_ID,%eax	# did EFLAGS.ID remained set?
+	jz .Lenable_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 .Lenable_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 .Lenable_paging
+
+	/* Check if extended functions are implemented */
+	movl $0x80000000, %eax
+	cpuid
+	/* Value must be in the range 0x80000001 to 0x8000ffff */
+	subl $0x80000001, %eax
+	cmpl $(0x8000ffff-0x80000001), %eax
+	ja .Lenable_paging
+
+	/* Clear bogus XD_DISABLE bits */
+	call verify_cpu
+
+	mov $0x80000001, %eax
+	cpuid
+	/* Execute Disable bit supported? */
+	btl $(X86_FEATURE_NX & 31), %edx
+	jnc .Lenable_paging
+
+	/* Setup EFER (Extended Feature Enable Register) */
+	movl $MSR_EFER, %ecx
+	rdmsr
+
+	btsl $_EFER_NX, %eax
+	/* Make changes effective */
+	wrmsr
+
+.Lenable_paging:
+
+/*
+ * Enable paging
+ */
+	movl $pa(initial_page_table), %eax
+	movl %eax,%cr3		/* set the page table pointer.. */
+	movl $CR0_STATE,%eax
+	movl %eax,%cr0		/* ..and set paging (PG) bit */
+	ljmp $__BOOT_CS,$1f	/* Clear prefetch and normalize %eip */
+1:
+	/* Shift the stack pointer to a virtual address */
+	addl $__PAGE_OFFSET, %esp
+
+/*
+ * start system 32-bit setup. We need to re-do some of the things done
+ * in 16-bit mode for the "real" operations.
+ */
+	movl setup_once_ref,%eax
+	andl %eax,%eax
+	jz 1f				# Did we do this already?
+	call *%eax
+1:
+
+/*
+ * Check if it is 486
+ */
+	movb $4,X86			# at least 486
+	cmpl $-1,X86_CPUID
+	je .Lis486
+
+	/* get vendor info */
+	xorl %eax,%eax			# call CPUID with 0 -> return vendor ID
+	cpuid
+	movl %eax,X86_CPUID		# save CPUID level
+	movl %ebx,X86_VENDOR_ID		# lo 4 chars
+	movl %edx,X86_VENDOR_ID+4	# next 4 chars
+	movl %ecx,X86_VENDOR_ID+8	# last 4 chars
+
+	orl %eax,%eax			# do we have processor info as well?
+	je .Lis486
+
+	movl $1,%eax		# Use the CPUID instruction to get CPU type
+	cpuid
+	movb %al,%cl		# save reg for future use
+	andb $0x0f,%ah		# mask processor family
+	movb %ah,X86
+	andb $0xf0,%al		# mask model
+	shrb $4,%al
+	movb %al,X86_MODEL
+	andb $0x0f,%cl		# mask mask revision
+	movb %cl,X86_STEPPING
+	movl %edx,X86_CAPABILITY
+
+.Lis486:
+	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
+
+	lgdt early_gdt_descr
+	ljmp $(__KERNEL_CS),$1f
+1:	movl $(__KERNEL_DS),%eax	# reload all the segment registers
+	movl %eax,%ss			# after changing gdt.
+
+	movl $(__USER_DS),%eax		# DS/ES contains default USER segment
+	movl %eax,%ds
+	movl %eax,%es
+
+	movl $(__KERNEL_PERCPU), %eax
+	movl %eax,%fs			# set this cpu's percpu
+
+	movl $(__KERNEL_STACK_CANARY),%eax
+	movl %eax,%gs
+
+	xorl %eax,%eax			# Clear LDT
+	lldt %ax
+
+	call *(initial_code)
+1:	jmp 1b
+ENDPROC(startup_32_smp)
+
+#include "verify_cpu.S"
+
+/*
+ *  setup_once
+ *
+ *  The setup work we only want to run on the BSP.
+ *
+ *  Warning: %esi is live across this function.
+ */
+__INIT
+setup_once:
+#ifdef CONFIG_STACKPROTECTOR
+	/*
+	 * Configure the stack canary. The linker can't handle this by
+	 * relocation.  Manually set base address in stack canary
+	 * segment descriptor.
+	 */
+	movl $gdt_page,%eax
+	movl $stack_canary,%ecx
+	movw %cx, 8 * GDT_ENTRY_STACK_CANARY + 2(%eax)
+	shrl $16, %ecx
+	movb %cl, 8 * GDT_ENTRY_STACK_CANARY + 4(%eax)
+	movb %ch, 8 * GDT_ENTRY_STACK_CANARY + 7(%eax)
+#endif
+
+	andl $0,setup_once_ref	/* Once is enough, thanks */
+	ret
+
+ENTRY(early_idt_handler_array)
+	# 36(%esp) %eflags
+	# 32(%esp) %cs
+	# 28(%esp) %eip
+	# 24(%rsp) error code
+	i = 0
+	.rept NUM_EXCEPTION_VECTORS
+	.if ((EXCEPTION_ERRCODE_MASK >> i) & 1) == 0
+	pushl $0		# Dummy error code, to make stack frame uniform
+	.endif
+	pushl $i		# 20(%esp) Vector number
+	jmp early_idt_handler_common
+	i = i + 1
+	.fill early_idt_handler_array + i*EARLY_IDT_HANDLER_SIZE - ., 1, 0xcc
+	.endr
+ENDPROC(early_idt_handler_array)
+	
+early_idt_handler_common:
+	/*
+	 * The stack is the hardware frame, an error code or zero, and the
+	 * vector number.
+	 */
+	cld
+
+	incl %ss:early_recursion_flag
+
+	/* The vector number is in pt_regs->gs */
+
+	cld
+	pushl	%fs		/* pt_regs->fs (__fsh varies by model) */
+	pushl	%es		/* pt_regs->es (__esh varies by model) */
+	pushl	%ds		/* pt_regs->ds (__dsh varies by model) */
+	pushl	%eax		/* pt_regs->ax */
+	pushl	%ebp		/* pt_regs->bp */
+	pushl	%edi		/* pt_regs->di */
+	pushl	%esi		/* pt_regs->si */
+	pushl	%edx		/* pt_regs->dx */
+	pushl	%ecx		/* pt_regs->cx */
+	pushl	%ebx		/* pt_regs->bx */
+
+	/* Fix up DS and ES */
+	movl	$(__KERNEL_DS), %ecx
+	movl	%ecx, %ds
+	movl	%ecx, %es
+
+	/* Load the vector number into EDX */
+	movl	PT_GS(%esp), %edx
+
+	/* Load GS into pt_regs->gs (and maybe clobber __gsh) */
+	movw	%gs, PT_GS(%esp)
+
+	movl	%esp, %eax	/* args are pt_regs (EAX), trapnr (EDX) */
+	call	early_fixup_exception
+
+	popl	%ebx		/* pt_regs->bx */
+	popl	%ecx		/* pt_regs->cx */
+	popl	%edx		/* pt_regs->dx */
+	popl	%esi		/* pt_regs->si */
+	popl	%edi		/* pt_regs->di */
+	popl	%ebp		/* pt_regs->bp */
+	popl	%eax		/* pt_regs->ax */
+	popl	%ds		/* pt_regs->ds (always ignores __dsh) */
+	popl	%es		/* pt_regs->es (always ignores __esh) */
+	popl	%fs		/* pt_regs->fs (always ignores __fsh) */
+	popl	%gs		/* pt_regs->gs (always ignores __gsh) */
+	decl	%ss:early_recursion_flag
+	addl	$4, %esp	/* pop pt_regs->orig_ax */
+	iret
+ENDPROC(early_idt_handler_common)
+
+/* This is the default interrupt "handler" :-) */
+ENTRY(early_ignore_irq)
+	cld
+#ifdef CONFIG_PRINTK
+	pushl %eax
+	pushl %ecx
+	pushl %edx
+	pushl %es
+	pushl %ds
+	movl $(__KERNEL_DS),%eax
+	movl %eax,%ds
+	movl %eax,%es
+	cmpl $2,early_recursion_flag
+	je hlt_loop
+	incl early_recursion_flag
+	pushl 16(%esp)
+	pushl 24(%esp)
+	pushl 32(%esp)
+	pushl 40(%esp)
+	pushl $int_msg
+	call printk
+
+	call dump_stack
+
+	addl $(5*4),%esp
+	popl %ds
+	popl %es
+	popl %edx
+	popl %ecx
+	popl %eax
+#endif
+	iret
+
+hlt_loop:
+	hlt
+	jmp hlt_loop
+ENDPROC(early_ignore_irq)
+
+__INITDATA
+	.align 4
+GLOBAL(early_recursion_flag)
+	.long 0
+
+__REFDATA
+	.align 4
+ENTRY(initial_code)
+	.long i386_start_kernel
+ENTRY(setup_once_ref)
+	.long setup_once
+
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
+#define	PGD_ALIGN	(2 * PAGE_SIZE)
+#define PTI_USER_PGD_FILL	1024
+#else
+#define	PGD_ALIGN	(PAGE_SIZE)
+#define PTI_USER_PGD_FILL	0
+#endif
+/*
+ * BSS section
+ */
+__PAGE_ALIGNED_BSS
+	.align PGD_ALIGN
+#ifdef CONFIG_X86_PAE
+.globl initial_pg_pmd
+initial_pg_pmd:
+	.fill 1024*KPMDS,4,0
+#else
+.globl initial_page_table
+initial_page_table:
+	.fill 1024,4,0
+#endif
+	.align PGD_ALIGN
+initial_pg_fixmap:
+	.fill 1024,4,0
+.globl swapper_pg_dir
+	.align PGD_ALIGN
+swapper_pg_dir:
+	.fill 1024,4,0
+	.fill PTI_USER_PGD_FILL,4,0
+.globl empty_zero_page
+empty_zero_page:
+	.fill 4096,1,0
+EXPORT_SYMBOL(empty_zero_page)
+
+/*
+ * This starts the data section.
+ */
+#ifdef CONFIG_X86_PAE
+__PAGE_ALIGNED_DATA
+	/* Page-aligned for the benefit of paravirt? */
+	.align PGD_ALIGN
+ENTRY(initial_page_table)
+	.long	pa(initial_pg_pmd+PGD_IDENT_ATTR),0	/* low identity map */
+# if KPMDS == 3
+	.long	pa(initial_pg_pmd+PGD_IDENT_ATTR),0
+	.long	pa(initial_pg_pmd+PGD_IDENT_ATTR+0x1000),0
+	.long	pa(initial_pg_pmd+PGD_IDENT_ATTR+0x2000),0
+# elif KPMDS == 2
+	.long	0,0
+	.long	pa(initial_pg_pmd+PGD_IDENT_ATTR),0
+	.long	pa(initial_pg_pmd+PGD_IDENT_ATTR+0x1000),0
+# elif KPMDS == 1
+	.long	0,0
+	.long	0,0
+	.long	pa(initial_pg_pmd+PGD_IDENT_ATTR),0
+# else
+#  error "Kernel PMDs should be 1, 2 or 3"
+# endif
+	.align PAGE_SIZE		/* needs to be page-sized too */
+#endif
+
+.data
+.balign 4
+ENTRY(initial_stack)
+	/*
+	 * The SIZEOF_PTREGS gap is a convention which helps the in-kernel
+	 * unwinder reliably detect the end of the stack.
+	 */
+	.long init_thread_union + THREAD_SIZE - SIZEOF_PTREGS - \
+	      TOP_OF_KERNEL_STACK_PADDING;
+
+__INITRODATA
+int_msg:
+	.asciz "Unknown interrupt or fault at: %p %p %p\n"
+
+#include "../../x86/xen/xen-head.S"
+
+/*
+ * The IDT and GDT 'descriptors' are a strange 48-bit object
+ * only used by the lidt and lgdt instructions. They are not
+ * like usual segment descriptors - they consist of a 16-bit
+ * segment size, and 32-bit linear address value:
+ */
+
+	.data
+.globl boot_gdt_descr
+
+	ALIGN
+# early boot GDT descriptor (must use 1:1 address mapping)
+	.word 0				# 32 bit align gdt_desc.address
+boot_gdt_descr:
+	.word __BOOT_DS+7
+	.long boot_gdt - __PAGE_OFFSET
+
+# boot GDT descriptor (later on used by CPU#0):
+	.word 0				# 32 bit align gdt_desc.address
+ENTRY(early_gdt_descr)
+	.word GDT_ENTRIES*8-1
+	.long gdt_page			/* Overwritten for secondary CPUs */
+
+/*
+ * The boot_gdt must mirror the equivalent in setup.S and is
+ * used only for booting.
+ */
+	.align L1_CACHE_BYTES
+ENTRY(boot_gdt)
+	.fill GDT_ENTRY_BOOT_CS,8,0
+	.quad 0x00cf9a000000ffff	/* kernel 4GB code at 0x00000000 */
+	.quad 0x00cf92000000ffff	/* kernel 4GB data at 0x00000000 */