From: Marc Zyngier <marc.zyngier@arm.com> To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Mark Salter <msalter@redhat.com>, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will.deacon@arm.com> Subject: [PATCH] arm64: fixmap: fix missing sub-page offset for earlyprintk Date: Mon, 28 Apr 2014 19:50:06 +0100 [thread overview] Message-ID: <1398711006-14943-1-git-send-email-marc.zyngier@arm.com> (raw) Commit d57c33c5daa4 (add generic fixmap.h) added (among other similar things) set_fixmap_io to deal with early ioremap of devices. More recently, commit bf4b558eba92 (arm64: add early_ioremap support) converted the arm64 earlyprintk to use set_fixmap_io. A side effect of this conversion is that my virtual machines have stopped booting when I pass "earlyprintk=uart8250-8bit,0x3f8" to the guest kernel. Turns out that the new earlyprintk code doesn't care at all about sub-page offsets, and just assumes that the earlyprintk device will be page-aligned. Obviously, that doesn't play well with the above example. Further investigation shows that set_fixmap_io uses __set_fixmap instead of __set_fixmap_offset. A fix is to introduce a set_fixmap_offset_io that uses the latter, and to remove the superflous call to fix_to_virt (which only returns the value that set_fixmap_io has already given us). With this applied, my VMs are back in business. Tested on a Cortex-A57 platform with kvmtool as platform emulation. Cc: Mark Salter <msalter@redhat.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> --- arch/arm64/kernel/early_printk.c | 6 ++---- include/asm-generic/fixmap.h | 3 +++ 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kernel/early_printk.c b/arch/arm64/kernel/early_printk.c index ffbbdde..2dc36d0 100644 --- a/arch/arm64/kernel/early_printk.c +++ b/arch/arm64/kernel/early_printk.c @@ -143,10 +143,8 @@ static int __init setup_early_printk(char *buf) } /* no options parsing yet */ - if (paddr) { - set_fixmap_io(FIX_EARLYCON_MEM_BASE, paddr); - early_base = (void __iomem *)fix_to_virt(FIX_EARLYCON_MEM_BASE); - } + if (paddr) + early_base = (void __iomem *)set_fixmap_offset_io(FIX_EARLYCON_MEM_BASE, paddr); printch = match->printch; early_console = &early_console_dev; diff --git a/include/asm-generic/fixmap.h b/include/asm-generic/fixmap.h index 5a64ca4..f23174f 100644 --- a/include/asm-generic/fixmap.h +++ b/include/asm-generic/fixmap.h @@ -93,5 +93,8 @@ static inline unsigned long virt_to_fix(const unsigned long vaddr) #define set_fixmap_io(idx, phys) \ __set_fixmap(idx, phys, FIXMAP_PAGE_IO) +#define set_fixmap_offset_io(idx, phys) \ + __set_fixmap_offset(idx, phys, FIXMAP_PAGE_IO) + #endif /* __ASSEMBLY__ */ #endif /* __ASM_GENERIC_FIXMAP_H */ -- 1.8.3.4
WARNING: multiple messages have this Message-ID (diff)
From: marc.zyngier@arm.com (Marc Zyngier) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH] arm64: fixmap: fix missing sub-page offset for earlyprintk Date: Mon, 28 Apr 2014 19:50:06 +0100 [thread overview] Message-ID: <1398711006-14943-1-git-send-email-marc.zyngier@arm.com> (raw) Commit d57c33c5daa4 (add generic fixmap.h) added (among other similar things) set_fixmap_io to deal with early ioremap of devices. More recently, commit bf4b558eba92 (arm64: add early_ioremap support) converted the arm64 earlyprintk to use set_fixmap_io. A side effect of this conversion is that my virtual machines have stopped booting when I pass "earlyprintk=uart8250-8bit,0x3f8" to the guest kernel. Turns out that the new earlyprintk code doesn't care at all about sub-page offsets, and just assumes that the earlyprintk device will be page-aligned. Obviously, that doesn't play well with the above example. Further investigation shows that set_fixmap_io uses __set_fixmap instead of __set_fixmap_offset. A fix is to introduce a set_fixmap_offset_io that uses the latter, and to remove the superflous call to fix_to_virt (which only returns the value that set_fixmap_io has already given us). With this applied, my VMs are back in business. Tested on a Cortex-A57 platform with kvmtool as platform emulation. Cc: Mark Salter <msalter@redhat.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> --- arch/arm64/kernel/early_printk.c | 6 ++---- include/asm-generic/fixmap.h | 3 +++ 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kernel/early_printk.c b/arch/arm64/kernel/early_printk.c index ffbbdde..2dc36d0 100644 --- a/arch/arm64/kernel/early_printk.c +++ b/arch/arm64/kernel/early_printk.c @@ -143,10 +143,8 @@ static int __init setup_early_printk(char *buf) } /* no options parsing yet */ - if (paddr) { - set_fixmap_io(FIX_EARLYCON_MEM_BASE, paddr); - early_base = (void __iomem *)fix_to_virt(FIX_EARLYCON_MEM_BASE); - } + if (paddr) + early_base = (void __iomem *)set_fixmap_offset_io(FIX_EARLYCON_MEM_BASE, paddr); printch = match->printch; early_console = &early_console_dev; diff --git a/include/asm-generic/fixmap.h b/include/asm-generic/fixmap.h index 5a64ca4..f23174f 100644 --- a/include/asm-generic/fixmap.h +++ b/include/asm-generic/fixmap.h @@ -93,5 +93,8 @@ static inline unsigned long virt_to_fix(const unsigned long vaddr) #define set_fixmap_io(idx, phys) \ __set_fixmap(idx, phys, FIXMAP_PAGE_IO) +#define set_fixmap_offset_io(idx, phys) \ + __set_fixmap_offset(idx, phys, FIXMAP_PAGE_IO) + #endif /* __ASSEMBLY__ */ #endif /* __ASM_GENERIC_FIXMAP_H */ -- 1.8.3.4
next reply other threads:[~2014-04-28 19:13 UTC|newest] Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-04-28 18:50 Marc Zyngier [this message] 2014-04-28 18:50 ` [PATCH] arm64: fixmap: fix missing sub-page offset for earlyprintk Marc Zyngier 2014-04-28 19:44 ` Mark Salter 2014-04-28 19:44 ` Mark Salter 2014-04-28 23:51 ` Rob Herring 2014-04-28 23:51 ` Rob Herring 2014-04-29 8:57 ` Catalin Marinas 2014-04-29 8:57 ` Catalin Marinas
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