| Message ID | 20180123212327.GN28231@n2100.armlinux.org.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi, On Tue, Jan 23, 2018 at 09:23:27PM +0000, Russell King - ARM Linux wrote: > On Tue, Jan 23, 2018 at 08:45:44PM +0000, Russell King - ARM Linux wrote: > > On Tue, Jan 23, 2018 at 12:06:54AM +0200, Aaro Koskinen wrote: > > > On Mon, Jan 15, 2018 at 10:15:08AM -0800, Tony Lindgren wrote: > > > > * Aaro Koskinen <aaro.koskinen@iki.fi> [180111 11:48]: > > > > > When booting v4.15-rc kernel with kexec (kexec-tools 2.0.16) on N8x0, I get: > > > > > > > > > > Uncompressing Linux... done, booting the kernel. > > > > > no ATAGS support: can't continue > > > > > > > > > > v4.14 kernel works OK. > > > > > > > > > > I bisected this to: > > > > > > > > > > commit c772568788b5f0cbaac7c8d4111d7173bfc90673 > > > > > Author: Russell King <rmk+kernel@armlinux.org.uk> > > > > > Date: Thu Sep 21 18:10:19 2017 +0100 > > > > > > > > > > ARM: add additional table to compressed kernel > > > > > > > > > > If I revert the commit, kexec booting starts to work. Interesting, > > > > > the patch mentions "This is necessary for correct behaviour of kexec.", > > > > > so I wonder what could be wrong... > > > > > > > > So care to post what you get if you load with kexec -d -l options > > > > before and after this commit? > > > > > > See below. I guess the interesting part is the "zImage has tags" with the > > > bad kernel. > > > > > > Bad (plain v4.15-rc9) > > > --------------------- > > > kernel: 0xb6a25008 kernel_size: 0x3ce605 > > > MEMORY RANGES > > > 0000000080000000-0000000087ffffff (0) > > > zImage header: 0x016f2818 0x00000000 0x003c59d0 > > > zImage size 0x3c59d0, file size 0x3ce605 > > > > This looks like you've appended a DTB blob to the zImage as the file > > is larger than the zImage says it should be. Yes. I have now disabled/removed the appended DTB, just in case, but it doesn't seem to make any difference. > > Right, so this says that this is a "modern" kernel that's being loaded > > with the additional tags in that tell kexec how much space the > > decompressed kernel requires. > > > > > kernel image size: 0x00c5c6ec > > > > and it requires this amount of space. > > > > > kexec_load: entry = 0x80008000 flags = 0x280000 > > > nr_segments = 2 > > > segment[0].buf = 0xb6a25008 > > > segment[0].bufsz = 0x3c59d0 > > > segment[0].mem = 0x80008000 > > > segment[0].memsz = 0x3c6000 > > > > This is the kernel, with the appended dtb removed. > > > > > segment[1].buf = 0x1ed52b8 > > > segment[1].bufsz = 0x8c35 > > > segment[1].mem = 0x80c66000 > > > segment[1].memsz = 0x9000 > > > > This is the DTB, placed out of the way from the kernel (the highest > > address the kernel will use while decompressing is 0x00c5c6ec + > > 0x80008000. Everything here looks correct. But something is still corrupting the DTB... > > > [ 4.850341] kexec_core: Starting new kernel > > > [ 4.854766] Bye! > > > > > > (kernel fails to boot) > > > > > > Good (v4.15-rc9 and c772568788b5f0cbaac7c8d4111d7173bfc90673 reverted) > > > ----------------------------- > > > kernel: 0xb6999008 kernel_size: 0x3ce9bd > > > MEMORY RANGES > > > 0000000080000000-0000000087ffffff (0) > > > zImage header: 0x016f2818 0x00000000 0x003c5d88 > > > zImage size 0x3c5d88, file size 0x3ce9bd > > > kexec_load: entry = 0x80008000 flags = 0x280000 > > > nr_segments = 2 > > > segment[0].buf = 0xb6999008 > > > segment[0].bufsz = 0x3c5d88 > > > segment[0].mem = 0x80008000 > > > segment[0].memsz = 0x3c6000 > > > > Here we have the same thing for the kernel. > > > > > segment[1].buf = 0x14192b8 > > > segment[1].bufsz = 0x8c35 > > > segment[1].mem = 0x812e7000 > > > segment[1].memsz = 0x9000 > > > > Here, the DTB is placed much further away. So, the "compression ratio 4 calculation" works better. > > It really doesn't help that it took ages for the kexec-tools patches > > to get merged, and when they did get merged, the wrong patch set was > > taken. Consequently, the debug above does not match my local source > > tree, and neither does the code. > > > > Sorry, but I'm afraid I can't debug this at the moment. > > Here's the delta between what _was_ merged and what I intended to be > merged: > > 8<===== > From: Russell King <rmk@armlinux.org.uk> > Subject: [PATCH] ARM: read kernel size from zImage I tried this, output looks different but the kernel is still unbootable. I also tried switching from XZ to GZIP decompressor, but it didn't help either. kernel: 0xb68e7008 kernel_size: 0x56cdf0 MEMORY RANGES 0000000080000000-0000000087ffffff (0) zImage header: 0x016f2818 0x00000000 0x0056cdf0 zImage size 0x56cdf0, file size 0x56cdf0 offset 0x000039c0 tag 0x5a534c4b size 8 Kernel: address=0x80008000 size=0x010b4d90 DT : address=0x810be000 size=0x00008c35 kexec_load: entry = 0x80008000 flags = 0x280000 nr_segments = 2 segment[0].buf = 0xb68e7008 segment[0].bufsz = 0x56cdf0 segment[0].mem = 0x80008000 segment[0].memsz = 0x56d000 segment[1].buf = 0x7622b8 segment[1].bufsz = 0x8c35 segment[1].mem = 0x810be000 segment[1].memsz = 0x9000 [ 5.070251] kexec_core: Starting new kernel [ 5.074676] Bye! Then I played around with kexec_arm_image_size in kexec-tools, and noticed that adding only 0x2000 gets booting to work: kernel: 0xb681f008 kernel_size: 0x56cdf0 MEMORY RANGES 0000000080000000-0000000087ffffff (0) zImage header: 0x016f2818 0x00000000 0x0056cdf0 zImage size 0x56cdf0, file size 0x56cdf0 offset 0x000039c0 tag 0x5a534c4b size 8 Kernel: address=0x80008000 size=0x010b6d90 DT : address=0x810c0000 size=0x00008c35 kexec_load: entry = 0x80008000 flags = 0x280000 nr_segments = 2 segment[0].buf = 0xb681f008 segment[0].bufsz = 0x56cdf0 segment[0].mem = 0x80008000 segment[0].memsz = 0x56d000 segment[1].buf = 0x9412b8 segment[1].bufsz = 0x8c35 segment[1].mem = 0x810c0000 segment[1].memsz = 0x9000 [ 5.070312] kexec_core: Starting new kernel [ 5.074737] Bye! [ 0.000000] Booting Linux on physical CPU 0x0 [ 0.000000] Linux version 4.15.0-rc9-n8x0-los_a513f+ (aaro@amd-fx-6350) (gcc version 6.4.0 (GCC)) #1 Wed Jan 24 21:30:47 EET 2018 [...] So something is missing from the size calculation...? A. -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/kexec/arch/arm/kexec-zImage-arm.c b/kexec/arch/arm/kexec-zImage-arm.c index a8c40cb6cd6a..76a0b5b66745 100644 --- a/kexec/arch/arm/kexec-zImage-arm.c +++ b/kexec/arch/arm/kexec-zImage-arm.c @@ -355,6 +355,34 @@ static int setup_dtb_prop(char **bufp, off_t *sizep, int parentoffset, return 0; } +static const struct zimage_tag *find_extension_tag(const char *buf, off_t len, + uint32_t tag_id) +{ + const struct zimage_header *hdr = (const struct zimage_header *)buf; + const struct zimage_tag *tag; + uint32_t offset, size; + uint32_t max = len - sizeof(struct tag_header); + + if (len < sizeof(*hdr) || + hdr->magic != ZIMAGE_MAGIC || + hdr->magic2 != ZIMAGE_MAGIC2) + return NULL; + + for (offset = hdr->extension_tag_offset; + (tag = (void *)(buf + offset)) != NULL && + offset < max && + (size = le32_to_cpu(byte_size(tag))) != 0 && + offset + size < len; + offset += size) { + dbgprintf(" offset 0x%08x tag 0x%08x size %u\n", + offset, le32_to_cpu(tag->hdr.tag), size); + if (tag->hdr.tag == tag_id) + return tag; + } + + return NULL; +} + int zImage_arm_load(int argc, char **argv, const char *buf, off_t len, struct kexec_info *info) { @@ -362,6 +390,7 @@ int zImage_arm_load(int argc, char **argv, const char *buf, off_t len, unsigned long base, kernel_base; unsigned int atag_offset = 0x1000; /* 4k offset from memory start */ unsigned int extra_size = 0x8000; /* TEXT_OFFSET */ + const struct zimage_tag *tag; size_t kernel_mem_size; const char *command_line; char *modified_cmdline = NULL; @@ -480,35 +509,6 @@ int zImage_arm_load(int argc, char **argv, const char *buf, off_t len, if (size < len) len = size; } - - /* Do we have an extension table? */ - if (hdr->magic2 == ZIMAGE_MAGIC2 && !kexec_arm_image_size) { - uint32_t offset = hdr->extension_tag_offset; - uint32_t max = len - sizeof(struct tag_header); - struct zimage_tag *tag; - - dbgprintf("zImage has tags\n"); - - for (offset = hdr->extension_tag_offset; - (tag = (void *)(buf + offset)) != NULL && - offset < max && byte_size(tag) && - offset + byte_size(tag) < len; - offset += byte_size(tag)) { - dbgprintf(" offset 0x%08x tag 0x%08x size %u\n", - offset, tag->hdr.tag, byte_size(tag)); - if (tag->hdr.tag == ZIMAGE_TAG_KRNL_SIZE) { - uint32_t *p = (void *)buf + - tag->u.krnl_size.size_ptr; - - kexec_arm_image_size = - get_unaligned(p) + - tag->u.krnl_size.bss_size; - } - } - - dbgprintf("kernel image size: 0x%08x\n", - kexec_arm_image_size); - } } /* Handle android images, 2048 is the minimum page size */ @@ -553,9 +553,40 @@ int zImage_arm_load(int argc, char **argv, const char *buf, off_t len, kernel_mem_size = len + 4; /* - * If the user didn't specify the size of the image, assume the - * maximum kernel compression ratio is 4. Note that we must - * include space for the compressed image here as well. + * Check for a kernel size extension, and set or validate the + * image size. This is the total space needed to avoid the + * boot kernel BSS, so other data (such as initrd) does not get + * overwritten. + */ + tag = find_extension_tag(buf, len, ZIMAGE_TAG_KRNL_SIZE); + if (tag) { + uint32_t *p = (void *)buf + le32_to_cpu(tag->u.krnl_size.size_ptr); + uint32_t edata_size = le32_to_cpu(get_unaligned(p)); + uint32_t bss_size = le32_to_cpu(tag->u.krnl_size.bss_size); + uint32_t kernel_size = edata_size + bss_size; + + /* + * While decompressing, the zImage is placed past _edata + * of the decompressed kernel. Ensure we account for that. + */ + if (kernel_size < edata_size + len) + kernel_size = edata_size + len; + + if (kexec_arm_image_size == 0) + kexec_arm_image_size = kernel_size; + else if (kexec_arm_image_size < kernel_size) { + fprintf(stderr, + "Kernel size is too small, increasing to 0x%lx\n", + (unsigned long)kernel_size); + kexec_arm_image_size = kernel_size; + } + } + + /* + * If the user didn't specify the size of the image, and we don't + * have the extension tables, assume the maximum kernel compression + * ratio is 4. Note that we must include space for the compressed + * image here as well. */ if (!kexec_arm_image_size) kexec_arm_image_size = len * 5; @@ -617,6 +648,10 @@ int zImage_arm_load(int argc, char **argv, const char *buf, off_t len, */ initrd_base = kernel_base + _ALIGN(kexec_arm_image_size, page_size); + dbgprintf("%-6s: address=0x%08lx size=0x%08lx\n", "Kernel", + (unsigned long)kernel_base, + (unsigned long)kexec_arm_image_size); + if (ramdisk_buf) { /* * Find a hole to place the initrd. The crash kernel use @@ -630,6 +665,10 @@ int zImage_arm_load(int argc, char **argv, const char *buf, off_t len, return -1; } + dbgprintf("%-6s: address=0x%08lx size=0x%08lx\n", "Initrd", + (unsigned long)initrd_base, + (unsigned long)initrd_size); + add_segment(info, ramdisk_buf, initrd_size, initrd_base, initrd_size); } @@ -708,6 +747,9 @@ int zImage_arm_load(int argc, char **argv, const char *buf, off_t len, return -1; } + dbgprintf("%-6s: address=0x%08lx size=0x%08lx\n", "DT", + (unsigned long)dtb_offset, (unsigned long)dtb_length); + add_segment(info, dtb_buf, dtb_length, dtb_offset, dtb_length); }