Re: [PATCH] Revert "MIPS: make userspace mapping young by default".

[Huang Pei]

On Sat, Apr 17, 2021 at 12:45:59AM +0800, Zhou Yanjie wrote:
> 
> On 2021/4/16 下午5:20, 黄沛 wrote:
> > Is there any log about the panic?
> 
> 
> Yes, below is the log:
> 
> 
> [  195.436017] CPU 0 Unable to handle kernel paging request at virtual
> address 77eb8000, epc == 80117868, ra == 80118208
> [  195.446709] Oops[#1]:
> [  195.448977] CPU: 0 PID: 1461 Comm: Xsession Not tainted
> 5.12.0-rc6-00227-gc8fc6defbd2e-dirty #1
> [  195.457661] $ 0   : 00000000 00000001 80117864 77eb9000
> [  195.462888] $ 4   : 77eb8000 82419600 838ea000 82482ba0
> [  195.468116] $ 8   : 826f8b18 8306f800 000072d5 8306f800
> [  195.473343] $12   : 00000002 00000a03 00000001 00000402
> [  195.478568] $16   : 77eb8000 809faf60 00000004 82482ba0
> [  195.483794] $20   : 77eb8000 82419600 82482ba0 80860000
> [  195.489021] $24   : 8086121c 80117864
> [  195.494248] $28   : 838ea000 838ebd70 00000000 80118208
> [  195.499475] Hi    : 00008c4e
> [  195.502343] Lo    : 00004627
> [  195.505212] epc   : 80117868 r4k_blast_dcache_page_dc32+0x4/0x9c
> [  195.511217] ra    : 80118208 local_r4k_flush_cache_page+0x120/0x1b8
> [  195.517476] Status: 10001403 KERNEL EXL IE
> [  195.521657] Cause : 4080800c (ExcCode 03)
> [  195.525654] BadVA : 77eb8000
> [  195.528523] PrId  : 00d00100 (Ingenic XBurst)
> [  195.532866] Modules linked in:
> [  195.535911] Process Xsession (pid: 1461, threadinfo=00975a3e,
> task=3724fd66, tls=77ebd690)
> [  195.544162] Stack : 808a05ec f7edcbfd 8306f800 00000000 80860000 809faf60
> 80990a3c 80117f90
> [  195.552524]         809faf60 82419600 8306f800 801fd84c 00000000 801180b4
> 838ebe80 80110b7c
> [  195.560887]         80990a3c 82482ba0 82482ba0 77eb8000 00004627 f7edcbfd
> 838ebe80 801cbc08
> [  195.569249]         00000001 181b2000 00000000 801fa06c 00000000 83999ae0
> 80860000 00000004
> [  195.577610]         80990a3c f7edcbfd 80990a3c 838ebe80 00000004 80990a3c
> 82482ba0 04627685
> [  195.585973]         ...
> [  195.588413] Call Trace:
> [  195.590849] [<80117868>] r4k_blast_dcache_page_dc32+0x4/0x9c
> [  195.596501] [<80118208>] local_r4k_flush_cache_page+0x120/0x1b8
> [  195.602413] [<80117f90>] r4k_on_each_cpu.isra.8+0x24/0x58
> [  195.607805] [<801180b4>] r4k_flush_cache_page+0x34/0x58
> [  195.613023] [<801cbc08>] wp_page_copy+0x3a8/0x56c
> [  195.617723] [<801ce944>] do_swap_page+0x4cc/0x558
> [  195.622419] [<801cf3f8>] handle_mm_fault+0x790/0x93c
> [  195.627374] [<8011025c>] do_page_fault+0x19c/0x540
> [  195.632159] [<801142f0>] tlb_do_page_fault_1+0x10c/0x11c
> [  195.637465]
> [  195.638947] Code: 03e00008  00000000  24831000 <bc950000> bc950020 
> bc950040  bc950060  bc950080  bc9500a0
> [  195.648706]
> [  195.650243] ---[ end trace 7cc7d7f611932c42 ]---
> [  195.654857] Kernel panic - not syncing: Fatal exception
> [  195.660072] Rebooting in 10 seconds..
> 
> 
> this problem can be triggered stably (by use Microsoft Remote Desktop client
> to login to debian9 running on CU1830-Neo).
> 
Could you print out the PTE value at 0x77eb8000 ?

I really have no idea of how the page_prot setting affecting the swap
handling.

> 
> Thanks and best regards!
> 
> 
> > 
> >    Original Message
> > From: 周琰杰 (Zhou Yanjie)
> > Sent: 2021年4月16日星期五 16:48
> > To: tsbogend@xxxxxxxxxxxxxxxx
> > Cc: linux-mips@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; akpm@xxxxxxxxxxxxxxxxxxxx; paul.burton@xxxxxxxx; paul@xxxxxxxxxxxxxxx; siyanteng@xxxxxxxxxxx; huangpei@xxxxxxxxxxx; ira.weiny@xxxxxxxxx; yangtiezhu@xxxxxxxxxxx; zhouyanjie@xxxxxxxxxxxxxx; jun.jiang@xxxxxxxxxxx; dongsheng.qiu@xxxxxxxxxxx; aric.pzqi@xxxxxxxxxxx; rick.tyliu@xxxxxxxxxxx; sernia.zhou@xxxxxxxxxxx
> > Subject: [PATCH] Revert "MIPS: make userspace mapping young by default".
> > 
> > This reverts commit f685a533a7fab35c5d069dcd663f59c8e4171a75.
> > 
> > It cause kernel panic on Ingenic X1830, so let's revert it.
> > 
> > Signed-off-by: 周琰杰 (Zhou Yanjie) <zhouyanjie@xxxxxxxxxxxxxx>
> > ---
> > arch/mips/mm/cache.c | 31 ++++++++++++++-----------------
> > 1 file changed, 14 insertions(+), 17 deletions(-)
> > 
> > diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c
> > index 7719d63..9cfd432 100644
> > --- a/arch/mips/mm/cache.c
> > +++ b/arch/mips/mm/cache.c
> > @@ -21,7 +21,6 @@
> > #include <asm/cpu.h>
> > #include <asm/cpu-features.h>
> > #include <asm/setup.h>
> > -#include <asm/pgtable.h>
> > 
> > /* Cache operations. */
> > void (*flush_cache_all)(void);
> > @@ -157,31 +156,29 @@ unsigned long _page_cachable_default;
> > EXPORT_SYMBOL(_page_cachable_default);
> > 
> > #define PM(p)	__pgprot(_page_cachable_default | (p))
> > -#define PVA(p)	PM(_PAGE_VALID | _PAGE_ACCESSED | (p))
> > 
> > static inline void setup_protection_map(void)
> > {
> > protection_map[0] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
> > -	protection_map[1] = PVA(_PAGE_PRESENT | _PAGE_NO_EXEC);
> > -	protection_map[2] = PVA(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
> > -	protection_map[3] = PVA(_PAGE_PRESENT | _PAGE_NO_EXEC);
> > -	protection_map[4] = PVA(_PAGE_PRESENT);
> > -	protection_map[5] = PVA(_PAGE_PRESENT);
> > -	protection_map[6] = PVA(_PAGE_PRESENT);
> > -	protection_map[7] = PVA(_PAGE_PRESENT);
> > +	protection_map[1] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC);
> > +	protection_map[2] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
> > +	protection_map[3] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC);
> > +	protection_map[4] = PM(_PAGE_PRESENT);
> > +	protection_map[5] = PM(_PAGE_PRESENT);
> > +	protection_map[6] = PM(_PAGE_PRESENT);
> > +	protection_map[7] = PM(_PAGE_PRESENT);
> > 
> > protection_map[8] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
> > -	protection_map[9] = PVA(_PAGE_PRESENT | _PAGE_NO_EXEC);
> > -	protection_map[10] = PVA(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE |
> > +	protection_map[9] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC);
> > +	protection_map[10] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE |
> > _PAGE_NO_READ);
> > -	protection_map[11] = PVA(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE);
> > -	protection_map[12] = PVA(_PAGE_PRESENT);
> > -	protection_map[13] = PVA(_PAGE_PRESENT);
> > -	protection_map[14] = PVA(_PAGE_PRESENT);
> > -	protection_map[15] = PVA(_PAGE_PRESENT);
> > +	protection_map[11] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE);
> > +	protection_map[12] = PM(_PAGE_PRESENT);
> > +	protection_map[13] = PM(_PAGE_PRESENT);
> > +	protection_map[14] = PM(_PAGE_PRESENT | _PAGE_WRITE);
> > +	protection_map[15] = PM(_PAGE_PRESENT | _PAGE_WRITE);
> > }
> > 
> > -#undef _PVA
> > #undef PM
> > 
> > void cpu_cache_init(void)