From 15426ca43d888e79f2dc4012bce0cbd6be96baf1 Mon Sep 17 00:00:00 2001 From: Vasily Gorbik Date: Wed, 11 Apr 2018 11:56:55 +0200 Subject: [PATCH] s390: rescue initrd as early as possible To avoid multi-stage initrd rescue operation and to simplify assumptions during early memory allocations move initrd at some final safe destination as early as possible. This would also allow us to drop .bss usage restrictions for some files. Reviewed-by: Martin Schwidefsky Signed-off-by: Vasily Gorbik Signed-off-by: Martin Schwidefsky --- arch/s390/boot/compressed/decompressor.h | 2 ++ arch/s390/boot/compressed/misc.c | 29 +++++++++++++---------------- arch/s390/boot/startup.c | 24 ++++++++++++++++++++++++ arch/s390/kernel/early_nobss.c | 22 ---------------------- arch/s390/kernel/vmlinux.lds.S | 1 + 5 files changed, 40 insertions(+), 38 deletions(-) diff --git a/arch/s390/boot/compressed/decompressor.h b/arch/s390/boot/compressed/decompressor.h index 011cbb6..90d382d 100644 --- a/arch/s390/boot/compressed/decompressor.h +++ b/arch/s390/boot/compressed/decompressor.h @@ -7,11 +7,13 @@ static inline void *decompress_kernel(void) {} #else void *decompress_kernel(void); #endif +unsigned long mem_safe_offset(void); struct vmlinux_info { unsigned long default_lma; void (*entry)(void); unsigned long image_size; /* does not include .bss */ + unsigned long bss_size; /* uncompressed image .bss size */ }; extern char _vmlinux_info[]; diff --git a/arch/s390/boot/compressed/misc.c b/arch/s390/boot/compressed/misc.c index 5dcf34e..b773f81 100644 --- a/arch/s390/boot/compressed/misc.c +++ b/arch/s390/boot/compressed/misc.c @@ -83,25 +83,22 @@ static void error(char *x) asm volatile("lpsw %0" : : "Q" (psw)); } -void *decompress_kernel(void) -{ - void *output, *kernel_end; - - output = (void *) ALIGN((unsigned long) _end + HEAP_SIZE, PAGE_SIZE); - kernel_end = output + vmlinux.image_size; +#define decompress_offset ALIGN((unsigned long)_end + HEAP_SIZE, PAGE_SIZE) -#ifdef CONFIG_BLK_DEV_INITRD +unsigned long mem_safe_offset(void) +{ /* - * Move the initrd right behind the end of the decompressed - * kernel image. This also prevents initrd corruption caused by - * bss clearing since kernel_end will always be located behind the - * current bss section.. + * due to 4MB HEAD_SIZE for bzip2 + * 'decompress_offset + vmlinux.image_size' could be larger than + * kernel at final position + its .bss, so take the larger of two */ - if (INITRD_START && INITRD_SIZE && kernel_end > (void *) INITRD_START) { - memmove(kernel_end, (void *) INITRD_START, INITRD_SIZE); - INITRD_START = (unsigned long) kernel_end; - } -#endif + return max(decompress_offset + vmlinux.image_size, + vmlinux.default_lma + vmlinux.image_size + vmlinux.bss_size); +} + +void *decompress_kernel(void) +{ + void *output = (void *)decompress_offset; __decompress(_compressed_start, _compressed_end - _compressed_start, NULL, NULL, output, 0, NULL, error); diff --git a/arch/s390/boot/startup.c b/arch/s390/boot/startup.c index 474dee8..5aeac75 100644 --- a/arch/s390/boot/startup.c +++ b/arch/s390/boot/startup.c @@ -1,12 +1,36 @@ // SPDX-License-Identifier: GPL-2.0 #include +#include #include "compressed/decompressor.h" #include "boot.h" +#ifdef CONFIG_KERNEL_UNCOMPRESSED +unsigned long mem_safe_offset(void) +{ + return vmlinux.default_lma + vmlinux.image_size + vmlinux.bss_size; +} +#endif + +static void rescue_initrd(void) +{ + unsigned long min_initrd_addr; + + if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD)) + return; + if (!INITRD_START || !INITRD_SIZE) + return; + min_initrd_addr = mem_safe_offset(); + if (min_initrd_addr <= INITRD_START) + return; + memmove((void *)min_initrd_addr, (void *)INITRD_START, INITRD_SIZE); + INITRD_START = min_initrd_addr; +} + void startup_kernel(void) { void *img; + rescue_initrd(); if (!IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED)) { img = decompress_kernel(); memmove((void *)vmlinux.default_lma, img, vmlinux.image_size); diff --git a/arch/s390/kernel/early_nobss.c b/arch/s390/kernel/early_nobss.c index 2d84fc4..8e96590 100644 --- a/arch/s390/kernel/early_nobss.c +++ b/arch/s390/kernel/early_nobss.c @@ -13,7 +13,6 @@ #include #include #include -#include #include #include "entry.h" @@ -32,26 +31,6 @@ static void __init reset_tod_clock(void) S390_lowcore.last_update_clock = TOD_UNIX_EPOCH; } -static void __init rescue_initrd(void) -{ - unsigned long min_initrd_addr = (unsigned long) _end + (4UL << 20); - - /* - * Just like in case of IPL from VM reader we make sure there is a - * gap of 4MB between end of kernel and start of initrd. - * That way we can also be sure that saving an NSS will succeed, - * which however only requires different segments. - */ - if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD)) - return; - if (!INITRD_START || !INITRD_SIZE) - return; - if (INITRD_START >= min_initrd_addr) - return; - memmove((void *) min_initrd_addr, (void *) INITRD_START, INITRD_SIZE); - INITRD_START = min_initrd_addr; -} - static void __init clear_bss_section(void) { memset(__bss_start, 0, __bss_stop - __bss_start); @@ -60,6 +39,5 @@ static void __init clear_bss_section(void) void __init startup_init_nobss(void) { reset_tod_clock(); - rescue_initrd(); clear_bss_section(); } diff --git a/arch/s390/kernel/vmlinux.lds.S b/arch/s390/kernel/vmlinux.lds.S index 4b59d1c..4c5358f 100644 --- a/arch/s390/kernel/vmlinux.lds.S +++ b/arch/s390/kernel/vmlinux.lds.S @@ -154,6 +154,7 @@ SECTIONS QUAD(_stext) /* default_lma */ QUAD(startup_continue) /* entry */ QUAD(__bss_start - _stext) /* image_size */ + QUAD(__bss_stop - __bss_start) /* bss_size */ } /* Debugging sections. */ -- 2.7.4