From: Michael Ellerman <mpe@ellerman.id.au>
To: Arnd Bergmann <arnd@arndb.de>,
Rohan McLure <rmclure@linux.ibm.com>,
linuxppc-dev@lists.ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail.com>
Subject: Re: [PATCH v6 13/25] powerpc: Remove direct call to mmap2 syscall handlers
Date: Fri, 30 Sep 2022 23:19:46 +1000 [thread overview]
Message-ID: <87h70pov7x.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <2be2c0f2-9b4b-46e7-a10e-1c17026e8f79@www.fastmail.com>
"Arnd Bergmann" <arnd@arndb.de> writes:
> On Wed, Sep 28, 2022, at 2:15 PM, Michael Ellerman wrote:
>
>> But I think it makes more sense to do the same as mmap2() and pass the
>> 4K offset through, and pass shift = PAGE_SHIFT - 12. I also borrowed the
>> "off_4k" name from arm64. End result:
>>
>> #ifdef CONFIG_COMPAT
>> COMPAT_SYSCALL_DEFINE6(mmap2,
>> unsigned long, addr, size_t, len,
>> unsigned long, prot, unsigned long, flags,
>> unsigned long, fd, unsigned long, off_4k)
>> {
>> return do_mmap2(addr, len, prot, flags, fd, off_4k, PAGE_SHIFT-12);
>> }
>> #endif
>>
>> With that my G5 boots again :)
>
> Any chance we can instead add a working compat_sys_mmap2/sys_mmap2
> in mm/mmap.c alongside the sys_mmap_pgoff implementation?
I've merged this, but happy to clean things up in a subsequent patch :)
> While sys_mmap_pgoff() was meant to replace the various sys_mmap2()
> implementations, I think it was ultimately a mistake, and we later
> converged on the sys_mmap2() calling conventions with 12 bits
> offset for almost all 32-bit architectures.
I only see 3 compat mmap2s:
$ gg "COMPAT_SYSCALL.*mmap2"
arch/arm64/kernel/sys32.c:COMPAT_SYSCALL_DEFINE6(aarch32_mmap2, unsigned long, addr, unsigned long, len,
arch/powerpc/kernel/syscalls.c:COMPAT_SYSCALL_DEFINE6(mmap2, unsigned long, addr, size_t, len,
arch/s390/kernel/compat_linux.c:COMPAT_SYSCALL_DEFINE1(s390_mmap2, struct mmap_arg_struct_emu31 __user *, arg)
s390 is weird.
The arm64 one and ours are similar, but we have the additional call to
arch_validate_prot(prot, addr). arm64 does implement arch_validate_prot().
Similar with mmap2, we call arch_validate_prot() but no one else does (why not?).
cheers
next prev parent reply other threads:[~2022-09-30 13:20 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-21 6:55 [PATCH v6 00/25] powerpc: Syscall wrapper and register clearing Rohan McLure
2022-09-21 6:55 ` [PATCH v6 01/25] powerpc: Remove asmlinkage from syscall handler definitions Rohan McLure
2022-09-21 6:55 ` [PATCH v6 02/25] powerpc: Save caller r3 prior to system_call_exception Rohan McLure
2022-09-21 6:55 ` [PATCH v6 03/25] powerpc: Add ZEROIZE_GPRS macros for register clears Rohan McLure
2022-09-21 6:55 ` [PATCH v6 04/25] powerpc/64s: Use {ZEROIZE,SAVE,REST}_GPRS macros in sc, scv 0 handlers Rohan McLure
2022-09-21 6:55 ` [PATCH v6 05/25] powerpc/32: Clarify interrupt restores with REST_GPR macro in entry_32.S Rohan McLure
2022-09-21 6:55 ` [PATCH v6 06/25] powerpc/64e: Clarify register saves and clears with {SAVE,ZEROIZE}_GPRS Rohan McLure
2022-09-21 6:55 ` [PATCH v6 07/25] powerpc/64s: Fix comment on interrupt handler prologue Rohan McLure
2022-09-21 6:55 ` [PATCH v6 08/25] powerpc: Fix fallocate and fadvise64_64 compat parameter combination Rohan McLure
2022-09-21 6:55 ` [PATCH v6 09/25] asm-generic: compat: Support BE for long long args in 32-bit ABIs Rohan McLure
2022-10-31 13:23 ` [PATCH] asm-generic: compat: fix compat_arg_u64 and compat_arg_u64_dual Andreas Schwab
2022-11-01 12:25 ` Michael Ellerman
2022-11-03 8:20 ` Christophe Leroy
2022-11-03 8:48 ` Arnd Bergmann
2022-09-21 6:55 ` [PATCH v6 10/25] powerpc: Use generic fallocate compatibility syscall Rohan McLure
2022-09-21 6:55 ` [PATCH v6 11/25] powerpc/32: Remove powerpc select specialisation Rohan McLure
2022-09-21 6:55 ` [PATCH v6 12/25] powerpc: Remove direct call to personality syscall handler Rohan McLure
2022-09-21 6:55 ` [PATCH v6 13/25] powerpc: Remove direct call to mmap2 syscall handlers Rohan McLure
2022-09-28 12:15 ` Michael Ellerman
2022-09-28 13:00 ` Arnd Bergmann
2022-09-30 13:19 ` Michael Ellerman [this message]
2022-09-30 14:09 ` Arnd Bergmann
2022-09-21 6:55 ` [PATCH v6 14/25] powerpc: Provide do_ppc64_personality helper Rohan McLure
2022-09-21 6:55 ` [PATCH v6 15/25] powerpc: Adopt SYSCALL_DEFINE for arch-specific syscall handlers Rohan McLure
2022-09-21 6:55 ` [PATCH v6 16/25] powerpc: Include all arch-specific syscall prototypes Rohan McLure
2022-09-21 6:55 ` [PATCH v6 17/25] powerpc: Enable compile-time check for syscall handlers Rohan McLure
2022-09-21 6:55 ` [PATCH v6 18/25] powerpc: Use common syscall handler type Rohan McLure
2022-09-21 6:55 ` [PATCH v6 19/25] powerpc: Remove high-order word clearing on compat syscall entry Rohan McLure
2022-09-23 7:40 ` Nicholas Piggin
2022-09-28 11:56 ` Michael Ellerman
2022-09-21 6:56 ` [PATCH v6 20/25] powerpc: Change system_call_exception calling convention Rohan McLure
2022-09-23 7:43 ` Nicholas Piggin
2022-09-21 6:56 ` [PATCH v6 21/25] powerpc: Provide syscall wrapper Rohan McLure
2022-09-23 7:50 ` Nicholas Piggin
2022-10-30 15:34 ` Andreas Schwab
2022-10-30 15:50 ` Andreas Schwab
2022-10-30 19:43 ` Arnd Bergmann
2022-10-30 20:05 ` Andreas Schwab
2022-10-31 3:09 ` Michael Ellerman
2022-10-31 14:47 ` [PATCH] powerpc/32: fix syscall wrappers with 64-bit arguments Andreas Schwab
2022-10-31 19:37 ` Arnd Bergmann
2022-11-01 12:25 ` Michael Ellerman
2022-09-21 6:56 ` [PATCH v6 22/25] powerpc/64s: Clear user GPRs in syscall interrupt entry Rohan McLure
2022-09-23 8:02 ` Nicholas Piggin
2022-10-31 23:22 ` Rohan McLure
2022-09-21 6:56 ` [PATCH v6 23/25] powerpc/64: Add INTERRUPT_SANITIZE_REGISTERS Kconfig Rohan McLure
2022-09-21 6:56 ` [PATCH v6 24/25] powerpc/64s: Clear gprs on interrupt routine entry in Book3S Rohan McLure
2022-09-21 6:56 ` [PATCH v6 25/25] powerpc/64e: Clear gprs on interrupt routine entry on Book3E Rohan McLure
2022-10-04 13:24 ` [PATCH v6 00/25] powerpc: Syscall wrapper and register clearing Michael Ellerman
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