Commit 236d70f8 authored by Alexander Gordeev's avatar Alexander Gordeev
Browse files

s390/boot: Do not rescue .vmlinux.relocs section 



The .vmlinux.relocs section is moved in front of the compressed
kernel. The interim section rescue step is avoided as result.

Suggested-by: default avatarSumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: default avatarAlexander Gordeev <agordeev@linux.ibm.com>
parent 56b1069c

arch/s390/boot/startup.c

+13 −22
Original line number Diff line number Diff line
@@ -185,26 +185,7 @@ static void kaslr_adjust_relocs(unsigned long min_addr, unsigned long max_addr, 
}



static void kaslr_adjust_got(unsigned long offset) {}

static void rescue_relocs(void) {}

static void free_relocs(void) {}

#else

static int *vmlinux_relocs_64_start;

static int *vmlinux_relocs_64_end;



static void rescue_relocs(void)

{

	unsigned long size = __vmlinux_relocs_64_end - __vmlinux_relocs_64_start;



	vmlinux_relocs_64_start = (void *)physmem_alloc_top_down(RR_RELOC, size, 0);

	vmlinux_relocs_64_end = (void *)vmlinux_relocs_64_start + size;

	memmove(vmlinux_relocs_64_start, __vmlinux_relocs_64_start, size);

}



static void free_relocs(void)

{

	physmem_free(RR_RELOC);

}



static void kaslr_adjust_relocs(unsigned long min_addr, unsigned long max_addr,

				unsigned long offset, unsigned long phys_offset)

{
@@ -212,7 +193,7 @@ static void kaslr_adjust_relocs(unsigned long min_addr, unsigned long max_addr, 
	long loc;



	/* Adjust R_390_64 relocations */

	for (reloc = vmlinux_relocs_64_start; reloc < vmlinux_relocs_64_end; reloc++) {

	for (reloc = (int *)__vmlinux_relocs_64_start; reloc < (int *)__vmlinux_relocs_64_end; reloc++) {

		loc = (long)*reloc + phys_offset;

		if (loc < min_addr || loc > max_addr)

			error("64-bit relocation outside of kernel!\n");
@@ -486,7 +467,6 @@ void startup_kernel(void) 
	detect_physmem_online_ranges(max_physmem_end);

	save_ipl_cert_comp_list();

	rescue_initrd(safe_addr, ident_map_size);

	rescue_relocs();



	if (kaslr_enabled())

		__kaslr_offset_phys = randomize_within_range(kernel_size, THREAD_SIZE, 0, ident_map_size);
@@ -498,6 +478,18 @@ void startup_kernel(void) 


	/* vmlinux decompression is done, shrink reserved low memory */

	physmem_reserve(RR_DECOMPRESSOR, 0, (unsigned long)_decompressor_end);



	/*

	 * In case KASLR is enabled the randomized location of .amode31

	 * section might overlap with .vmlinux.relocs section. To avoid that

	 * the below randomize_within_range() could have been called with

	 * __vmlinux_relocs_64_end as the lower range address. However,

	 * .amode31 section is written to by the decompressed kernel - at

	 * that time the contents of .vmlinux.relocs is not needed anymore.

	 * Conversly, .vmlinux.relocs is read only by the decompressor, even

	 * before the kernel started. Therefore, in case the two sections

	 * overlap there is no risk of corrupting any data.

	 */

	if (kaslr_enabled())

		amode31_lma = randomize_within_range(vmlinux.amode31_size, PAGE_SIZE, 0, SZ_2G);

	if (!amode31_lma)
@@ -521,7 +513,6 @@ void startup_kernel(void) 
	kaslr_adjust_relocs(__kaslr_offset_phys, __kaslr_offset_phys + vmlinux.image_size,

			    __kaslr_offset, __kaslr_offset_phys);

	kaslr_adjust_got(__kaslr_offset);

	free_relocs();

	setup_vmem(__kaslr_offset, __kaslr_offset + kernel_size, asce_limit);

	copy_bootdata();

arch/s390/boot/vmlinux.lds.S

+9 −18
Original line number Diff line number Diff line
@@ -99,6 +99,15 @@ SECTIONS 


	_decompressor_end = .;



#ifndef CONFIG_PIE_BUILD

	. = ALIGN(4);

	.vmlinux.relocs : {

		__vmlinux_relocs_64_start = .;

		*(.vmlinux.relocs_64)

		__vmlinux_relocs_64_end = .;

	}

#endif



#ifdef CONFIG_KERNEL_UNCOMPRESSED

	. = ALIGN(PAGE_SIZE);

	. += AMODE31_SIZE;		/* .amode31 section */
@@ -111,24 +120,6 @@ SECTIONS 
		_compressed_end = .;

	}



#ifndef CONFIG_PIE_BUILD

	/*

	 * When the kernel is built with CONFIG_KERNEL_UNCOMPRESSED, the entire

	 * uncompressed vmlinux.bin is positioned in the bzImage decompressor

	 * image at the default kernel LMA of 0x100000, enabling it to be

	 * executed in-place. However, the size of .vmlinux.relocs could be

	 * large enough to cause an overlap with the uncompressed kernel at the

	 * address 0x100000. To address this issue, .vmlinux.relocs is

	 * positioned after the .rodata.compressed.

	 */

	. = ALIGN(4);

	.vmlinux.relocs : {

		__vmlinux_relocs_64_start = .;

		*(.vmlinux.relocs_64)

		__vmlinux_relocs_64_end = .;

	}

#endif



#define SB_TRAILER_SIZE 32

	/* Trailer needed for Secure Boot */

	. += SB_TRAILER_SIZE; /* make sure .sb.trailer does not overwrite the previous section */

arch/s390/include/asm/physmem_info.h

+0 −1
Original line number Diff line number Diff line
@@ -22,7 +22,6 @@ enum reserved_range_type { 
	RR_DECOMPRESSOR,

	RR_INITRD,

	RR_VMLINUX,

	RR_RELOC,

	RR_AMODE31,

	RR_IPLREPORT,

	RR_CERT_COMP_LIST,