Expose efi_entry() as the PE/COFF entrypoint directly, instead of
jumping into a wrapper that fiddles with stack buffers and other
stuff that the compiler is much better at. The only reason this
code exists is to obtain a pointer to the base of the image, but
we can get the same value from the loaded_image protocol, which
we already need for other reasons anyway.
Update the return type as well, to make it consistent with what
is required for a PE/COFF executable entrypoint.
Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
---
Apologies to Atish for making him track a moving target, but this is another
bit of cleanup work that I would like to merge before taking the RISC-V
changes on top.
On RISC-V, I would expect efi_enter_kernel() to be implemented as a C routine
that finds the hart id in the DT (which is passed as an argument), and pass
it to the startup code of the kernel proper.
arch/arm/boot/compressed/efi-header.S | 2 +-
arch/arm/boot/compressed/head.S | 44 +++-----------
arch/arm64/kernel/efi-entry.S | 64 +++-----------------
arch/arm64/kernel/efi-header.S | 2 +-
drivers/firmware/efi/libstub/arm-stub.c | 37 +++++------
drivers/firmware/efi/libstub/arm32-stub.c | 1 +
drivers/firmware/efi/libstub/arm64-stub.c | 3 +-
7 files changed, 42 insertions(+), 111 deletions(-)
diff --git a/arch/arm/boot/compressed/efi-header.S b/arch/arm/boot/compressed/efi-header.S
index a5983588f96b..e38fbda02b93 100644
--- a/arch/arm/boot/compressed/efi-header.S
+++ b/arch/arm/boot/compressed/efi-header.S
@@ -60,7 +60,7 @@ optional_header:
.long __pecoff_code_size @ SizeOfCode
.long __pecoff_data_size @ SizeOfInitializedData
.long 0 @ SizeOfUninitializedData
- .long efi_stub_entry - start @ AddressOfEntryPoint
+ .long efi_entry - start @ AddressOfEntryPoint
.long start_offset @ BaseOfCode
.long __pecoff_data_start - start @ BaseOfData
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index 088b0a060876..941cd28a13c3 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -1437,50 +1437,22 @@ __enter_kernel:
reloc_code_end:
#ifdef CONFIG_EFI_STUB
- .align 2
-_start: .long start - .
-
-ENTRY(efi_stub_entry)
- @ allocate space on stack for passing current zImage address
- @ and for the EFI stub to return of new entry point of
- @ zImage, as EFI stub may copy the kernel. Pointer address
- @ is passed in r2. r0 and r1 are passed through from the
- @ EFI firmware to efi_entry
- adr ip, _start
- ldr r3, [ip]
- add r3, r3, ip
- stmfd sp!, {r3, lr}
- mov r2, sp @ pass zImage address in r2
- bl efi_entry
-
- @ Check for error return from EFI stub. r0 has FDT address
- @ or error code.
- cmn r0, #1
- beq efi_load_fail
-
- @ Preserve return value of efi_entry() in r4
- mov r4, r0
+ENTRY(efi_enter_kernel)
+ mov r4, r0 @ preserve entrypoint
+ mov r5, r1 @ preserve DT pointer
bl cache_clean_flush
bl cache_off
@ Set parameters for booting zImage according to boot protocol
- @ put FDT address in r2, it was returned by efi_entry()
- @ r1 is the machine type, and r0 needs to be 0
mov r0, #0
mov r1, #0xFFFFFFFF
- mov r2, r4
+ mov r2, r5
- @ Branch to (possibly) relocated zImage that is in [sp]
- ldr lr, [sp]
+ @ Branch to (possibly) relocated zImage @ [r4]
ldr ip, =start_offset
- add lr, lr, ip
- mov pc, lr @ no mode switch
-
-efi_load_fail:
- @ Return EFI_LOAD_ERROR to EFI firmware on error.
- ldr r0, =0x80000001
- ldmfd sp!, {ip, pc}
-ENDPROC(efi_stub_entry)
+ add r4, r4, ip
+ mov pc, r4 @ no mode switch
+ENDPROC(efi_enter_kernel)
#endif
.align
diff --git a/arch/arm64/kernel/efi-entry.S b/arch/arm64/kernel/efi-entry.S
index 304d5b02ca67..49e3b1ad1b36 100644
--- a/arch/arm64/kernel/efi-entry.S
+++ b/arch/arm64/kernel/efi-entry.S
@@ -10,55 +10,18 @@
#include <asm/assembler.h>
-#define EFI_LOAD_ERROR 0x8000000000000001
-
__INIT
- /*
- * We arrive here from the EFI boot manager with:
- *
- * * CPU in little-endian mode
- * * MMU on with identity-mapped RAM
- * * Icache and Dcache on
- *
- * We will most likely be running from some place other than where
- * we want to be. The kernel image wants to be placed at TEXT_OFFSET
- * from start of RAM.
- */
-ENTRY(entry)
- /*
- * Create a stack frame to save FP/LR with extra space
- * for image_addr variable passed to efi_entry().
- */
- stp x29, x30, [sp, #-32]!
- mov x29, sp
-
- /*
- * Call efi_entry to do the real work.
- * x0 and x1 are already set up by firmware. Current runtime
- * address of image is calculated and passed via *image_addr.
- *
- * unsigned long efi_entry(void *handle,
- * efi_system_table_t *sys_table,
- * unsigned long *image_addr) ;
- */
- adr_l x8, _text
- add x2, sp, 16
- str x8, [x2]
- bl efi_entry
- cmn x0, #1
- b.eq efi_load_fail
-
+ENTRY(efi_enter_kernel)
/*
* efi_entry() will have copied the kernel image if necessary and we
- * return here with device tree address in x0 and the kernel entry
- * point stored at *image_addr. Save those values in registers which
- * are callee preserved.
+ * end up here with device tree address in x1 and the kernel entry
+ * point stored in x0. Save those values in registers which are
+ * callee preserved.
*/
- mov x20, x0 // DTB address
- ldr x0, [sp, #16] // relocated _text address
+ mov x20, x1 // DTB address
ldr w21, =stext_offset
- add x21, x0, x21
+ add x21, x0, x21 // relocated Image address
/*
* Calculate size of the kernel Image (same for original and copy).
@@ -80,9 +43,8 @@ ENTRY(entry)
* entries for the VA range of the current image, so no maintenance is
* necessary.
*/
- adr x0, entry
- adr x1, entry_end
- sub x1, x1, x0
+ adr x0, efi_enter_kernel
+ mov x1, efi_enter_kernel_size
bl __flush_dcache_area
/* Turn off Dcache and MMU */
@@ -110,11 +72,5 @@ ENTRY(entry)
mov x2, xzr
mov x3, xzr
br x21
-
-efi_load_fail:
- mov x0, #EFI_LOAD_ERROR
- ldp x29, x30, [sp], #32
- ret
-
-entry_end:
-ENDPROC(entry)
+ENDPROC(efi_enter_kernel)
+ .set efi_enter_kernel_size, . - efi_enter_kernel
diff --git a/arch/arm64/kernel/efi-header.S b/arch/arm64/kernel/efi-header.S
index a7cfacce3e15..40c704c5d3a5 100644
--- a/arch/arm64/kernel/efi-header.S
+++ b/arch/arm64/kernel/efi-header.S
@@ -27,7 +27,7 @@ optional_header:
.long __initdata_begin - efi_header_end // SizeOfCode
.long __pecoff_data_size // SizeOfInitializedData
.long 0 // SizeOfUninitializedData
- .long __efistub_entry - _head // AddressOfEntryPoint
+ .long __efistub_efi_entry - _head // AddressOfEntryPoint
.long efi_header_end - _head // BaseOfCode
extra_header_fields:
diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c
index 56e475c1aa55..439c094f7bf2 100644
--- a/drivers/firmware/efi/libstub/arm-stub.c
+++ b/drivers/firmware/efi/libstub/arm-stub.c
@@ -133,17 +133,20 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
unsigned long *reserve_size,
unsigned long dram_base,
efi_loaded_image_t *image);
+
+void __noreturn efi_enter_kernel(unsigned long entrypoint, unsigned long fdt);
+
/*
* EFI entry point for the arm/arm64 EFI stubs. This is the entrypoint
* that is described in the PE/COFF header. Most of the code is the same
* for both archictectures, with the arch-specific code provided in the
* handle_kernel_image() function.
*/
-unsigned long efi_entry(void *handle, efi_system_table_t *sys_table_arg,
- unsigned long *image_addr)
+efi_status_t efi_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg)
{
efi_loaded_image_t *image;
efi_status_t status;
+ unsigned long image_addr;
unsigned long image_size = 0;
unsigned long dram_base;
/* addr/point and size pairs for memory management*/
@@ -153,7 +156,6 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table_arg,
unsigned long fdt_size = 0;
char *cmdline_ptr = NULL;
int cmdline_size = 0;
- unsigned long new_fdt_addr;
efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID;
unsigned long reserve_addr = 0;
unsigned long reserve_size = 0;
@@ -165,8 +167,10 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table_arg,
sys_table = sys_table_arg;
/* Check if we were booted by the EFI firmware */
- if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
+ if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) {
+ status = EFI_INVALID_PARAMETER;
goto fail;
+ }
status = check_platform_features();
if (status != EFI_SUCCESS)
@@ -187,6 +191,7 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table_arg,
dram_base = get_dram_base();
if (dram_base == EFI_ERROR) {
pr_efi_err("Failed to find DRAM base\n");
+ status = EFI_LOAD_ERROR;
goto fail;
}
@@ -198,6 +203,7 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table_arg,
cmdline_ptr = efi_convert_cmdline(image, &cmdline_size, ULONG_MAX);
if (!cmdline_ptr) {
pr_efi_err("getting command line via LOADED_IMAGE_PROTOCOL\n");
+ status = EFI_OUT_OF_RESOURCES;
goto fail;
}
@@ -213,7 +219,7 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table_arg,
si = setup_graphics();
- status = handle_kernel_image(image_addr, &image_size,
+ status = handle_kernel_image(&image_addr, &image_size,
&reserve_addr,
&reserve_size,
dram_base, image);
@@ -260,7 +266,7 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table_arg,
pr_efi("Generating empty DTB\n");
if (!noinitrd()) {
- max_addr = efi_get_max_initrd_addr(dram_base, *image_addr);
+ max_addr = efi_get_max_initrd_addr(dram_base, image_addr);
status = efi_load_initrd_dev_path(&initrd_addr, &initrd_size,
max_addr);
if (status == EFI_SUCCESS) {
@@ -311,33 +317,30 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table_arg,
install_memreserve_table();
- new_fdt_addr = fdt_addr;
status = allocate_new_fdt_and_exit_boot(handle,
- &new_fdt_addr, efi_get_max_fdt_addr(dram_base),
+ &fdt_addr, efi_get_max_fdt_addr(dram_base),
initrd_addr, initrd_size, cmdline_ptr,
fdt_addr, fdt_size);
+ if (status != EFI_SUCCESS)
+ goto fail_free_initrd;
- /*
- * If all went well, we need to return the FDT address to the
- * calling function so it can be passed to kernel as part of
- * the kernel boot protocol.
- */
- if (status == EFI_SUCCESS)
- return new_fdt_addr;
+ efi_enter_kernel(image_addr, fdt_addr);
+ /* not reached */
+fail_free_initrd:
pr_efi_err("Failed to update FDT and exit boot services\n");
efi_free(initrd_size, initrd_addr);
efi_free(fdt_size, fdt_addr);
fail_free_image:
- efi_free(image_size, *image_addr);
+ efi_free(image_size, image_addr);
efi_free(reserve_size, reserve_addr);
fail_free_cmdline:
free_screen_info(si);
efi_free(cmdline_size, (unsigned long)cmdline_ptr);
fail:
- return EFI_ERROR;
+ return status;
}
/*
diff --git a/drivers/firmware/efi/libstub/arm32-stub.c b/drivers/firmware/efi/libstub/arm32-stub.c
index 7b2a6382b647..113298b8ea65 100644
--- a/drivers/firmware/efi/libstub/arm32-stub.c
+++ b/drivers/firmware/efi/libstub/arm32-stub.c
@@ -227,6 +227,7 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
* Relocate the zImage, so that it appears in the lowest 128 MB
* memory window.
*/
+ *image_addr = image->image_base;
*image_size = image->image_size;
status = efi_relocate_kernel(image_addr, *image_size, *image_size,
kernel_base + MAX_UNCOMP_KERNEL_SIZE, 0, 0);
diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c
index 719d03a64329..9254cd8ab2d3 100644
--- a/drivers/firmware/efi/libstub/arm64-stub.c
+++ b/drivers/firmware/efi/libstub/arm64-stub.c
@@ -43,7 +43,6 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
{
efi_status_t status;
unsigned long kernel_size, kernel_memsize = 0;
- void *old_image_addr = (void *)*image_addr;
unsigned long preferred_offset;
u64 phys_seed = 0;
@@ -141,7 +140,7 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
}
*image_addr = *reserve_addr + TEXT_OFFSET;
}
- memcpy((void *)*image_addr, old_image_addr, kernel_size);
+ memcpy((void *)*image_addr, image->image_base, kernel_size);
return EFI_SUCCESS;
}
--
2.17.1
