| Message ID | 1307858800-16712-3-git-send-email-nicolas.pitre@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sun, Jun 12, 2011 at 02:06:39AM -0400, Nicolas Pitre wrote: > From: John Bonesio <bones@secretlab.ca> > > This patch provides the ability to boot using a device tree that is appended > to the raw binary zImage (e.g. cat zImage <filename>.dtb > zImage_w_dtb). > > Signed-off-by: John Bonesio <bones@secretlab.ca> > [nico: adjusted to latest zImage changes plus additional cleanups] > Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org> Acked-by: Grant Likely <grant.likely@secretlab.ca> > --- > arch/arm/Kconfig | 8 ++++ > arch/arm/boot/compressed/head.S | 70 +++++++++++++++++++++++++++++++++++++-- > 2 files changed, 75 insertions(+), 3 deletions(-) > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > index 9adc278..66b7d1e 100644 > --- a/arch/arm/Kconfig > +++ b/arch/arm/Kconfig > @@ -1727,6 +1727,14 @@ config ZBOOT_ROM_MMCIF > which in turn loads the rest the kernel image to RAM using the > MMCIF hardware block. > > +config ARM_APPENDED_DTB > + bool "Use appended device tree blob to zImage" > + depends on OF && !ZBOOT_ROM > + help > + With this option, the boot code will look for a device tree binary > + (dtb) appended to zImage > + (e.g. cat zImage <filename>.dtb > zImage_w_dtb). > + > config CMDLINE > string "Default kernel command string" > default "" > diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S > index f9da419..4bc009c 100644 > --- a/arch/arm/boot/compressed/head.S > +++ b/arch/arm/boot/compressed/head.S > @@ -216,6 +216,59 @@ restart: adr r0, LC0 > mov r10, r6 > #endif > > + mov r5, #0 @ init dtb size to 0 > +#ifdef CONFIG_ARM_APPENDED_DTB > +/* > + * r0 = delta > + * r2 = BSS start > + * r3 = BSS end > + * r4 = final kernel address > + * r5 = appended dtb size (still unknown) > + * r6 = _edata > + * r7 = architecture ID > + * r8 = atags/device tree pointer > + * r9 = size of decompressed image > + * r10 = end of this image, including bss/stack/malloc space if non XIP > + * r11 = GOT start > + * r12 = GOT end > + * sp = stack pointer > + * > + * if there are device trees (dtb) appended to zImage, advance r10 so that the > + * dtb data will get relocated along with the kernel if necessary. > + */ > + > + ldr lr, [r6, #0] > +#ifndef __ARMEB__ > + ldr r1, =0xedfe0dd0 @ sig is 0xd00dfeed big endian > +#else > + ldr r1, =0xd00dfeed > +#endif > + cmp lr, r1 > + bne dtb_check_done @ not found > + > + mov r8, r6 @ use the appended device tree > + > + /* Get the dtb's size */ > + ldr r5, [r6, #4] > +#ifndef __ARMEB__ > + /* convert lr (dtb size) to little endian */ > + eor r1, r5, r5, ror #16 > + bic r1, r1, #0x00ff0000 > + mov r5, r5, ror #8 > + eor r5, r5, r1, lsr #8 > +#endif > + > + /* preserve 64-bit alignment */ > + add r5, r5, #7 > + bic r5, r5, #7 > + > + /* relocate some pointers past the appended dtb */ > + add r6, r6, r5 > + add r10, r10, r5 > + add sp, sp, r5 > +dtb_check_done: > +#endif > + > /* > * Check to see if we will overwrite ourselves. > * r4 = final kernel address > @@ -285,14 +338,16 @@ wont_overwrite: > * r2 = BSS start > * r3 = BSS end > * r4 = kernel execution address > + * r5 = appended dtb size (0 if not present) > * r7 = architecture ID > * r8 = atags pointer > * r11 = GOT start > * r12 = GOT end > * sp = stack pointer > */ > - teq r0, #0 > + orrs r1, r0, r5 > beq not_relocated > + > add r11, r11, r0 > add r12, r12, r0 > > @@ -307,12 +362,21 @@ wont_overwrite: > > /* > * Relocate all entries in the GOT table. > + * Bump bss entries to _edata + dtb size > */ > 1: ldr r1, [r11, #0] @ relocate entries in the GOT > - add r1, r1, r0 @ table. This fixes up the > - str r1, [r11], #4 @ C references. > + add r1, r1, r0 @ This fixes up C references > + cmp r1, r2 @ if entry >= bss_start && > + cmphs r3, r1 @ bss_end > entry > + addhi r1, r1, r5 @ entry += dtb size > + str r1, [r11], #4 @ next entry > cmp r11, r12 > blo 1b > + > + /* bump our bss pointers too */ > + add r2, r2, r5 > + add r3, r3, r5 > + > #else > > /* > -- > 1.7.4 >
* Nicolas Pitre <nicolas.pitre@linaro.org> [110611 23:03]: > From: John Bonesio <bones@secretlab.ca> > > This patch provides the ability to boot using a device tree that is appended > to the raw binary zImage (e.g. cat zImage <filename>.dtb > zImage_w_dtb). > > Signed-off-by: John Bonesio <bones@secretlab.ca> > [nico: adjusted to latest zImage changes plus additional cleanups] > Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org> Looks like this rebased version has two nice improvments: It uses r5 instead of lr, and keeps stack usable early on :) Acked-by: Tony Lindgren <tony@atomide.com>
On Mon, Jun 13, 2011 at 03:46:49AM -0700, Tony Lindgren wrote: > * Nicolas Pitre <nicolas.pitre@linaro.org> [110611 23:03]: > > From: John Bonesio <bones@secretlab.ca> > > > > This patch provides the ability to boot using a device tree that is appended > > to the raw binary zImage (e.g. cat zImage <filename>.dtb > zImage_w_dtb). > > > > Signed-off-by: John Bonesio <bones@secretlab.ca> > > [nico: adjusted to latest zImage changes plus additional cleanups] > > Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org> > > Looks like this rebased version has two nice improvments: It uses r5 > instead of lr, and keeps stack usable early on :) One of the comments still refers to lr though.
On Mon, 13 Jun 2011, Russell King - ARM Linux wrote: > On Mon, Jun 13, 2011 at 03:46:49AM -0700, Tony Lindgren wrote: > > * Nicolas Pitre <nicolas.pitre@linaro.org> [110611 23:03]: > > > From: John Bonesio <bones@secretlab.ca> > > > > > > This patch provides the ability to boot using a device tree that is appended > > > to the raw binary zImage (e.g. cat zImage <filename>.dtb > zImage_w_dtb). > > > > > > Signed-off-by: John Bonesio <bones@secretlab.ca> > > > [nico: adjusted to latest zImage changes plus additional cleanups] > > > Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org> > > > > Looks like this rebased version has two nice improvments: It uses r5 > > instead of lr, and keeps stack usable early on :) > > One of the comments still refers to lr though. Heh. Fixed. Nicolas
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 9adc278..66b7d1e 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1727,6 +1727,14 @@ config ZBOOT_ROM_MMCIF which in turn loads the rest the kernel image to RAM using the MMCIF hardware block. +config ARM_APPENDED_DTB + bool "Use appended device tree blob to zImage" + depends on OF && !ZBOOT_ROM + help + With this option, the boot code will look for a device tree binary + (dtb) appended to zImage + (e.g. cat zImage <filename>.dtb > zImage_w_dtb). + config CMDLINE string "Default kernel command string" default "" diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S index f9da419..4bc009c 100644 --- a/arch/arm/boot/compressed/head.S +++ b/arch/arm/boot/compressed/head.S @@ -216,6 +216,59 @@ restart: adr r0, LC0 mov r10, r6 #endif + mov r5, #0 @ init dtb size to 0 +#ifdef CONFIG_ARM_APPENDED_DTB +/* + * r0 = delta + * r2 = BSS start + * r3 = BSS end + * r4 = final kernel address + * r5 = appended dtb size (still unknown) + * r6 = _edata + * r7 = architecture ID + * r8 = atags/device tree pointer + * r9 = size of decompressed image + * r10 = end of this image, including bss/stack/malloc space if non XIP + * r11 = GOT start + * r12 = GOT end + * sp = stack pointer + * + * if there are device trees (dtb) appended to zImage, advance r10 so that the + * dtb data will get relocated along with the kernel if necessary. + */ + + ldr lr, [r6, #0] +#ifndef __ARMEB__ + ldr r1, =0xedfe0dd0 @ sig is 0xd00dfeed big endian +#else + ldr r1, =0xd00dfeed +#endif + cmp lr, r1 + bne dtb_check_done @ not found + + mov r8, r6 @ use the appended device tree + + /* Get the dtb's size */ + ldr r5, [r6, #4] +#ifndef __ARMEB__ + /* convert lr (dtb size) to little endian */ + eor r1, r5, r5, ror #16 + bic r1, r1, #0x00ff0000 + mov r5, r5, ror #8 + eor r5, r5, r1, lsr #8 +#endif + + /* preserve 64-bit alignment */ + add r5, r5, #7 + bic r5, r5, #7 + + /* relocate some pointers past the appended dtb */ + add r6, r6, r5 + add r10, r10, r5 + add sp, sp, r5 +dtb_check_done: +#endif + /* * Check to see if we will overwrite ourselves. * r4 = final kernel address @@ -285,14 +338,16 @@ wont_overwrite: * r2 = BSS start * r3 = BSS end * r4 = kernel execution address + * r5 = appended dtb size (0 if not present) * r7 = architecture ID * r8 = atags pointer * r11 = GOT start * r12 = GOT end * sp = stack pointer */ - teq r0, #0 + orrs r1, r0, r5 beq not_relocated + add r11, r11, r0 add r12, r12, r0 @@ -307,12 +362,21 @@ wont_overwrite: /* * Relocate all entries in the GOT table. + * Bump bss entries to _edata + dtb size */ 1: ldr r1, [r11, #0] @ relocate entries in the GOT - add r1, r1, r0 @ table. This fixes up the - str r1, [r11], #4 @ C references. + add r1, r1, r0 @ This fixes up C references + cmp r1, r2 @ if entry >= bss_start && + cmphs r3, r1 @ bss_end > entry + addhi r1, r1, r5 @ entry += dtb size + str r1, [r11], #4 @ next entry cmp r11, r12 blo 1b + + /* bump our bss pointers too */ + add r2, r2, r5 + add r3, r3, r5 + #else /*