Patch "powerpc/boot: Fix the early OPAL console wrappers" has been added to the 4.8-stable tree
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This is a note to let you know that I've just added the patch titled
powerpc/boot: Fix the early OPAL console wrappers
to the 4.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
powerpc-boot-fix-the-early-opal-console-wrappers.patch
and it can be found in the queue-4.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.
Quoted 1 line
From
a1ff57416af9a7971a801d553cd53edd8afb28d6Mon Sep 17 00:00:00 2001
From: Oliver O'Halloran <[email protected]>
Date: Wed, 23 Nov 2016 13:55:13 +1100
Subject: powerpc/boot: Fix the early OPAL console wrappers
From: Oliver O'Halloran <[email protected]>
commit a1ff57416af9a7971a801d553cd53edd8afb28d6 upstream.
When configured with CONFIG_PPC_EARLY_DEBUG_OPAL=y the kernel expects the OPAL entry and base addresses to be passed in r8 and r9 respectively. Currently the wrapper does not attempt to restore these values before entering the decompressed kernel which causes the kernel to branch into whatever happens to be in r9 when doing a write to the OPAL console in early boot.
This patch adds a platform_ops hook that can be used to branch into the new kernel. The OPAL console driver patches this at runtime so that if the console is used it will be restored just prior to entering the kernel.
--- arch/powerpc/boot/main.c | 8 ++++++-- arch/powerpc/boot/opal-calls.S | 13 +++++++++++++ arch/powerpc/boot/opal.c | 11 +++++++++++ arch/powerpc/boot/ops.h | 1 + 4 files changed, 31 insertions(+), 2 deletions(-)
arch/powerpc/boot/main.c +6 -2
@@ -217,8 +217,12 @@ void start(void) console_ops.close (); kentry = (kernel_entry_t ) vmlinux.addr; -if (ft_addr) -kentry (ft_addr,0 ,NULL ); +if (ft_addr) { +if (platform_ops.kentry) + platform_ops.kentry (ft_addr, vmlinux.addr); +else +kentry (ft_addr,0 ,NULL ); + }else kentry ((unsigned long )initrd.addr, initrd.size, loader_info.promptr);
arch/powerpc/boot/opal-calls.S +13 -0
@@ -12,6 +12,19 @@ .text + .globl opal_kentry +opal_kentry: + /* r3 is the fdt ptr */ + mtctr r4 + li r4, 0 + li r5, 0 + li r6, 0 + li r7, 0 + ld r11,opal@got(r2) + ld r8,0(r11) + ld r9,8(r11) + bctr + #define OPAL_CALL(name, token) \ .globl name; \ name: \
arch/powerpc/boot/opal.c +11 -0
@@ -23,14 +23,25 @@ struct opal {static u32 opal_con_id; +/* see opal-wrappers.S */ int64_t opal_console_write (int64_t term_number,u64 *length,const u8 *buffer);int64_t opal_console_read (int64_t term_number,uint64_t *length,u8 *buffer);int64_t opal_console_write_buffer_space (uint64_t term_number,uint64_t *length);int64_t opal_console_flush (uint64_t term_number);int64_t opal_poll_events (uint64_t *outstanding_event_mask); +void opal_kentry (unsigned long fdt_addr,void *vmlinux_addr); +static int opal_con_open (void ) { +/* +* When OPAL loads the boot kernel it stashes the OPAL base and entry +* address in r8 and r9 so the kernel can use the OPAL console +* before unflattening the devicetree. While executing the wrapper will +* probably trash r8 and r9 so this kentry hook restores them before +* entering the decompressed kernel. +*/ + platform_ops.kentry = opal_kentry;return 0 ; }
arch/powerpc/boot/ops.h +1 -0
@@ -30,6 +30,7 @@ struct platform_ops {void * (*realloc)(void *ptr,unsigned long size);void (*exit)(void );void * (*vmlinux_alloc)(unsigned long size); +void (*kentry)(unsigned long fdt_addr,void *vmlinux_addr); };extern struct platform_ops platform_ops;
Patches currently in stable-queue which might be from [email protected] are
queue-4.8/powerpc-boot-fix-the-early-opal-console-wrappers.patch