Messages in this thread Patch in this message |  | | Subject | Re: [PATCH v5 0/6] Move swapper_pg_dir to rodata section. | From | James Morse <> | Date | Wed, 3 Oct 2018 14:33:56 +0100 |
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Hi Catalin, Mark,
On 25/09/18 15:06, Mark Rutland wrote: > On Tue, Sep 25, 2018 at 05:53:16PM +0800, Jun Yao wrote: >> On Mon, Sep 24, 2018 at 06:19:36PM +0100, Mark Rutland wrote: >>> I've pushed a branch with the cleanups I requested [1] folded in. >>> >>> I'm still a bit worried about the pgd lock, but otherwise I think this >>> is sound. I intend to throw some testing at it, just in case. >>> >>> If you're happy with that branch, I'll ask Will and Catalin to consider >>> picking it up. >> >> This branch looks great. Thank you for improving my patch. > > Thanks for your patches! > >> Is there anything I need to do? This is my first time to submit a patch, >> so I am a bit overwhelmed. I think I should wait for other people to >> review my patch. If there is a problem, I need to fix it. > > Hopefully Catalin is happy to pick this up from my branch, and neither > of us have to do anything. :) > > Catalin, are you happy to pick the patches from: > > git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git arm64/ro-swapper > > ... that should be based on the arm64 for-next/core branch, and has > James's R-B prior to my commit fixup notes. > > I've given this some basic testing with defconfig, 48-bit/4k and > 42-bit/64k (with lockdep on in both cases), and things seem fine.
Re-running my hacky tests for this series knocks for-next/core over: | Unable to handle kernel write to read-only memory at virtual address fffffc00092b0008 | Mem abort info: | ESR = 0x9600004f | Exception class = DABT (current EL), IL = 32 bits | SET = 0, FnV = 0 | EA = 0, S1PTW = 0 | Data abort info: | ISV = 0, ISS = 0x0000004f | CM = 0, WnR = 1 | swapper pgtable: 64k pages, 42-bit VAs, pgdp = 00000000992f9c42 | [fffffc00092b0008] pgd=00000087ffff0803, pud=00000087ffff0803, pmd=00000087ffff0803, pte=00e00080032b0f93 | Internal error: Oops: 9600004f [#1] PREEMPT SMP | Modules linked in: | CPU: 4 PID: 13938 Comm: hackbench Tainted: G W 4.19.0-rc2-00063-gc219bc4e9205 #10628 | Hardware name: AMD Seattle (Rev.B0) Development Board (Overdrive) (DT) | pstate: a0400005 (NzCv daif +PAN -UAO) | pc : __pte_alloc_kernel+0x60/0xd8 | lr : __pte_alloc_kernel+0x44/0xd8
| Process hackbench (pid: 13938, stack limit = 0x000000007ca756ec) | Call trace: | __pte_alloc_kernel+0x60/0xd8 | vmap_page_range_noflush+0x1bc/0x1d8 | map_vm_area+0x30/0x40 | __vmalloc_node_range+0x1e4/0x2e8 | copy_process.isra.3.part.4+0x1e8/0x1ae8 | _do_fork+0xd0/0x7f0 | __arm64_sys_clone+0x1c/0x28
| el0_svc_handler+0x7c/0x130
| el0_svc+0x8/0xc
| Code: 90007b60 f946e000 cb000273 b2400673 (f9000293)
| ---[ end trace 7bf2d2ffce498c7a ]---
| Kernel panic - not syncing: Fatal exception
The below patch fixes it: I'll post it properly shortly... -----------------------%<----------------------- Author: James Morse <james.morse@arm.com> Date: Wed Oct 3 12:03:38 2018 +0100
asm-generic/pgtable-nop?d.h: define folded with a value for use in C
It turns out "if (__is_defined(__PAGETABLE_PMD_FOLDED))" isn't equivalent to "#ifdef __PAGETABLE_PMD_FOLDED". (who knew!)
kconfig.h's __is_defined() expects a define of the form "#define CONFIG_BOOGER 1". But these nop?d headers just have "#define __PAGETABLE_PMD_FOLDED".
This means ____is_defined()'s triplet passed to __take_second_arg() is 'empty-string 1 0' in both cases, meaning these symbols can't be used from C. (they are always false).
asm-generic gets away with this as its using the pre-processor's defined() macro on this, not the C __is_defined().
Add the expected '1'.
Signed-off-by: James Morse <james.morse@arm.com>
diff --git a/include/asm-generic/pgtable-nopmd.h b/include/asm-generic/pgtable-nopmd.h index f35f6e8149e4..fcb4769a075a 100644 --- a/include/asm-generic/pgtable-nopmd.h +++ b/include/asm-generic/pgtable-nopmd.h @@ -8,7 +8,7 @@
struct mm_struct;
-#define __PAGETABLE_PMD_FOLDED +#define __PAGETABLE_PMD_FOLDED 1
/* * Having the pmd type consist of a pud gets the size right, and allows diff --git a/include/asm-generic/pgtable-nopud.h b/include/asm-generic/pgtable-nopud.h index e950b9c50f34..d300dbcddaf3 100644 --- a/include/asm-generic/pgtable-nopud.h +++ b/include/asm-generic/pgtable-nopud.h @@ -9,7 +9,7 @@ #else #include <asm-generic/pgtable-nop4d.h>
-#define __PAGETABLE_PUD_FOLDED +#define __PAGETABLE_PUD_FOLDED 1
/* * Having the pud type consist of a p4d gets the size right, and allows -----------------------%<-----------------------
(and, while digging through this, I spotted: | #define set_pmd_at(mm, addr, pmdp, pmd) | set_pte_at(mm, addr, (pte_t *)pmdp, pmd_pte(pmd)) which may trip up too)
Thanks,
James
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