7d4155e6e6
Since linux commit f9ba70535dc12d9eb57d466a2ecd749e16eca866 "[PATCH] Increase number of e820 entries hard limit from 32 to 128" made in 2005 the number of e820 entries passed from the bootloader is 128. Use the boot protocol version to check for support of 128 entries and use them if necessary. Tested on IBM/SBP1: Fixes booting a Linux payload when more than 32 entries are present in the memory table, which can easily happen on a 4 socket platform. Change-Id: Iec0a832fff091b6c3ae7050ef63e743a30618f25 Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/80544 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Marvin Drees <marvin.drees@9elements.com> Reviewed-by: Maximilian Brune <maximilian.brune@9elements.com> Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
197 lines
5.1 KiB
ArmAsm
197 lines
5.1 KiB
ArmAsm
/* linux_trampoline */
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/* SPDX-License-Identifier: GPL-2.0-only */
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/* NOTE: THIS CODE MUST REMAIN POSITION INDEPENDENT
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* IT SHOULDN'T USE THE STACK
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* AND IN GENERAL EXPECT NOTHING BUT RAM TO WORK
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*/
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.code32
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.data
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#include "linux_trampoline.h"
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#define HEADER_SIG 0x4f49424c // LBIO little endian
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#define CB_TAG_FORWARD 0x11
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#define CB_TAG_MEMORY 0x1
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#define CB_TAG_FRAMEBUFFER 0x12
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#define CB_TAG_ACPI_RSDP 0x43
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#define ACPI_RSDP_ADDR 0x70
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#define E820_NR_OFFSET 0x1e8
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#define PROTOCOL_VERSION 0x206
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#define LINUX_ENTRY_OFFSET 0x214
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#define E820_OFFSET 0x2d0
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.trampoline_start:
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cld
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xor %edx, %edx
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mov $0, %ecx
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.headerSearch:
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mov $0x10000, %ebx
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add %ecx, %ebx
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mov (%ecx), %eax
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cmp $HEADER_SIG, %eax
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je .headerSearchDone // found the header
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add $16, %ecx
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cmp %ecx, %ebx
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jne .headerSearch
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.headerSearchDone:
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cmp %ecx, %ebx // reached the end == not found anything?
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je 2f // give up
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// we assume the checksum is okay, no test
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mov 4(%ecx), %ebx
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add %ecx, %ebx // ebx = cb_header + header_bytes
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mov 20(%ecx), %ecx // ecx = table_entries
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.tableScan:
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cmp $CB_TAG_FORWARD, (%ebx)
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jne .testMemory
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/* forward tag: assume 32bit pointer */
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mov 8(%ebx), %ecx
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jmp .headerSearch
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.testMemory:
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cmp $CB_TAG_MEMORY, (%ebx)
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jne .testAcpiRsdp
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/* memory tag: copy e820 map and entry count. also determine alt_mem_k */
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mov 4(%ebx), %eax
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sub $8, %eax
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shr $2, %eax /* eax = number of dwords of e820 data */
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/*
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* Historically linux had space for 32 entries. This limit was increased in
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* the year 2005 (Linux 2.6.11) to hold up to 128 entries.
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* Assume 128 entries when the boot protocol version is 2.04+.
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*/
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cmpw $0x0204, (LINUX_PARAM_LOC + PROTOCOL_VERSION)
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jge .e820big /* protocol version >= 2.04 can handle 128 entries of 5 dwords */
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cmp $(32 * 5), %eax /* linux wants at most 32 entries of 5 dwords */
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jng 1f
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mov $(32 * 5), %eax /* only copy 32 entries */
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jmp 1f
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.e820big:
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cmp $(128 * 5), %eax /* linux wants at most 128 entries of 5 dwords */
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jng 1f
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mov $(128 * 5), %eax /* only copy 128 entries */
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1:
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mov %eax, %esi
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mov $5, %edi
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div %edi
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mov %eax, (LINUX_PARAM_LOC + E820_NR_OFFSET)
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mov %esi, %eax
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xchg %eax, %ecx
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lea 8(%ebx), %esi /* e820 data source */
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mov $(LINUX_PARAM_LOC + E820_OFFSET), %edi
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rep movsl
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xchg %eax, %ecx
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/* e820 and LB_TAG_MEMORY type don't fully match: remap unknown type to 2, reserved memory */
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mov (LINUX_PARAM_LOC + E820_NR_OFFSET), %eax
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mov $(LINUX_PARAM_LOC + E820_OFFSET), %edi
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.test_e820_entry:
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cmp $0, %eax
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je .endScan
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cmp $12, 16(%edi) /* type */
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jng .next_e820_entry
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/* Fixup the type to 2, reserved memory */
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mov $2, 16(%edi)
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.next_e820_entry:
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dec %eax
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add $20, %edi
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jmp .test_e820_entry
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.testAcpiRsdp:
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cmp $CB_TAG_ACPI_RSDP, (%ebx)
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jne .testFramebuffer
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mov 8(%ebx), %eax
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mov %eax, (LINUX_PARAM_LOC + ACPI_RSDP_ADDR)
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mov 12(%ebx), %eax
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mov %eax, (LINUX_PARAM_LOC + ACPI_RSDP_ADDR + 4)
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jmp .endScan
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.testFramebuffer:
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cmp $CB_TAG_FRAMEBUFFER, (%ebx)
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jne .endScan
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cmpw $0x020f, (LINUX_PARAM_LOC + PROTOCOL_VERSION)
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jge .framebufferSetup /* protocol version >= 2.15 can handle 64-bit address */
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cmpl $0, 0x0c(%ebx) /* check if upper 32-bit of framebuffer address are 0 */
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jne .endScan
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.framebufferSetup:
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mov $LINUX_PARAM_LOC, %edi /* translate the framebuffer entry into Linux' struct screen_info */
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mov 0x08(%ebx), %eax /* physical_address */
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mov %eax, 0x18(%edi) /* -> lfb_base */
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mov 0x0c(%ebx), %eax /* physical_address */
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mov %eax, 0x3a(%edi) /* -> ext_lfb_base */
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mov 0x10(%ebx), %eax /* x_resolution */
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mov %ax, 0x12(%edi) /* -> lfb_width */
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mov 0x14(%ebx), %eax /* y_resolution */
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mov %ax, 0x14(%edi) /* -> lfb_height */
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mov 0x18(%ebx), %edx /* bytes_per_line */
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mov %dx, 0x24(%edi) /* -> lfb_linelength */
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mul %edx /* bytes_per_line * y_resolution */
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mov %eax, 0x1c(%edi) /* -> lfb_size */
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movzbw 0x1c(%ebx), %ax /* bits_per_pixel */
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mov %ax, 0x16(%edi) /* -> lfb_depth */
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mov $4, %esi /* Copy 4 color components' pos and size, each 1 byte. */
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1:
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mov 0x1b(%ebx, %esi, 2), %ax
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rol %ax /* Order is reversed for Linux, hence swap. */
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mov %ax, 0x24(%edi, %esi, 2)
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dec %esi
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jnz 1b
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#define VIDEO_CAPABILITY_64BIT_BASE (1 << 1)
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movl $VIDEO_CAPABILITY_64BIT_BASE, 0x36(%edi)
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#define LFB_EFI_SIMPLE 0x70 /* VIDEO_TYPE_EFI in Linux */
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movb $LFB_EFI_SIMPLE, 0x0f(%edi) /* -> orig_video_isVGA */
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.endScan:
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add 4(%ebx), %ebx
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dec %ecx
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jnz .tableScan
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/* Setup basic code and data segment selectors for Linux
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**
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** Flat code segment descriptor:
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** selector: 0x10
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** base : 0x00000000
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** limit : 0xFFFFFFFF
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** type : code, execute, read
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**
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** Flat data segment descriptor:
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** selector: 0x18
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** base : 0x00000000
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** limit : 0xFFFFFFFF
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** type : data, read/write
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**
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** Use TRAMPOLINE_ENTRY_LOC as a scratchpad.
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*/
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mov $TRAMPOLINE_ENTRY_LOC, %eax
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movl $0x0000ffff, 16(%eax) // Set up the 2 new descriptors
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movl $0x00cf9b00, 20(%eax)
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movl $0x0000ffff, 24(%eax)
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movl $0x00cf9300, 28(%eax)
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movb $0x2b, 0(%eax) // Set the size
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movl %eax, 2(%eax) // Set pointer to new GDT
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lgdt (%eax) // Load it
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/* finally: jump to kernel */
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mov $LINUX_PARAM_LOC, %esi
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jmp *(LINUX_PARAM_LOC + LINUX_ENTRY_OFFSET)
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2:
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hlt
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jmp 2b
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.trampoline_end:
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