From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Andrew Jeffery <andrew@aj.id.au>
Cc: oleg@redhat.com, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ARM: Implement functions for HAVE_FUNCTION_ARG_ACCESS_API
Date: Tue, 19 May 2020 16:02:04 +0100 [thread overview]
Message-ID: <20200519150204.GG1551@shell.armlinux.org.uk> (raw)
In-Reply-To: <20200519143132.603579-1-andrew@aj.id.au>
On Wed, May 20, 2020 at 12:01:32AM +0930, Andrew Jeffery wrote:
> This allows extraction of kernel function arguments via kprobes on ARM.
> Based on the arm64 implementation and adapted for the 32-bit AAPCS.
>
> Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
> ---
> The description for HAVE_FUNCTION_ARG_ACCESS_API was pretty vague on what was
> required. I've implemented enough to enable argument extraction for kprobes; is
> there anything else needed to satisfy HAVE_FUNCTION_ARG_ACCESS_API?
What about 64-bit arguments? How do they get handled?
regs_get_kernel_argument() talks about 'n' being the argument number,
and maps this directly to a register. If a function argument
prototype is:
(something *foo, long long bar, int baz)
The foo is in r0, bar is in r2/r3 on EABI, and baz is on the stack.
n=0 will return foo. n=1 will be undefined. n=2 will return part of
bar, and n=3 will return the other half. Is this what is expected?
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC for 0.8m (est. 1762m) line in suburbia: sync at 13.1Mbps down 424kbps up
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next prev parent reply other threads:[~2020-05-19 15:02 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-19 14:31 [PATCH] ARM: Implement functions for HAVE_FUNCTION_ARG_ACCESS_API Andrew Jeffery
2020-05-19 15:02 ` Russell King - ARM Linux admin [this message]
2020-05-20 0:44 ` Andrew Jeffery
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