![Arnd Bergmann](/assets/img/avatar_default.png)
After several hours of debugging this obviously bogus but elaborate gcc-7.0.1 warning, drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c: In function 'vchiq_complete_bulk': drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c:603:4: error: argument 2 null where non-null expected [-Werror=nonnull] memcpy((char *)page_address(pages[0]) + ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ pagelist->offset, ~~~~~~~~~~~~~~~~~ fragments, ~~~~~~~~~~ head_bytes); ~~~~~~~~~~~ In file included from include/linux/string.h:18:0, from include/linux/bitmap.h:8, from include/linux/cpumask.h:11, from include/linux/interrupt.h:9, from drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c:37: arch/arm/include/asm/string.h:16:15: note: in a call to function 'memcpy' declared here extern void * memcpy(void *, const void *, __kernel_size_t) __nocapture(2); ^~~~~~ I have concluded that gcc was technically right in the first place: vchiq_complete_bulk is an externally visible function that calls free_pagelist(), which in turn derives a pointer from the global g_fragments_base variable. g_fragments_base is initialized in vchiq_platform_init(), but we only get there if of_property_read_u32() successfully reads the cache line size. When CONFIG_OF is disabled, this always fails, and g_fragments_base is guaranteed to be NULL when vchiq_complete_bulk() gets called. This adds a CONFIG_OF Kconfig dependency, which is also technically correct but nonobvious, and thus seems like a good fit for the warning. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
12 lines
356 B
Plaintext
12 lines
356 B
Plaintext
config BCM2835_VCHIQ
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tristate "Videocore VCHIQ"
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depends on HAS_DMA
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depends on OF
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depends on RASPBERRYPI_FIRMWARE || (COMPILE_TEST && !RASPBERRYPI_FIRMWARE)
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default y
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help
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Kernel to VideoCore communication interface for the
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BCM2835 family of products.
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Defaults to Y when the Broadcom Videocore services
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are included in the build, N otherwise.
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