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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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1a91a36aba
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20200226223125.GA20630@embeddedor
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
79 lines
2.3 KiB
C
79 lines
2.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
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#ifndef LINUX_MMC_IOCTL_H
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#define LINUX_MMC_IOCTL_H
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#include <linux/types.h>
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struct mmc_ioc_cmd {
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/*
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* Direction of data: nonzero = write, zero = read.
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* Bit 31 selects 'Reliable Write' for RPMB.
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*/
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int write_flag;
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/* Application-specific command. true = precede with CMD55 */
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int is_acmd;
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__u32 opcode;
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__u32 arg;
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__u32 response[4]; /* CMD response */
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unsigned int flags;
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unsigned int blksz;
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unsigned int blocks;
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/*
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* Sleep at least postsleep_min_us useconds, and at most
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* postsleep_max_us useconds *after* issuing command. Needed for
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* some read commands for which cards have no other way of indicating
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* they're ready for the next command (i.e. there is no equivalent of
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* a "busy" indicator for read operations).
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*/
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unsigned int postsleep_min_us;
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unsigned int postsleep_max_us;
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/*
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* Override driver-computed timeouts. Note the difference in units!
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*/
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unsigned int data_timeout_ns;
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unsigned int cmd_timeout_ms;
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/*
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* For 64-bit machines, the next member, ``__u64 data_ptr``, wants to
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* be 8-byte aligned. Make sure this struct is the same size when
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* built for 32-bit.
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*/
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__u32 __pad;
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/* DAT buffer */
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__u64 data_ptr;
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};
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#define mmc_ioc_cmd_set_data(ic, ptr) ic.data_ptr = (__u64)(unsigned long) ptr
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/**
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* struct mmc_ioc_multi_cmd - multi command information
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* @num_of_cmds: Number of commands to send. Must be equal to or less than
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* MMC_IOC_MAX_CMDS.
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* @cmds: Array of commands with length equal to 'num_of_cmds'
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*/
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struct mmc_ioc_multi_cmd {
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__u64 num_of_cmds;
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struct mmc_ioc_cmd cmds[];
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};
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#define MMC_IOC_CMD _IOWR(MMC_BLOCK_MAJOR, 0, struct mmc_ioc_cmd)
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/*
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* MMC_IOC_MULTI_CMD: Used to send an array of MMC commands described by
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* the structure mmc_ioc_multi_cmd. The MMC driver will issue all
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* commands in array in sequence to card.
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*/
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#define MMC_IOC_MULTI_CMD _IOWR(MMC_BLOCK_MAJOR, 1, struct mmc_ioc_multi_cmd)
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/*
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* Since this ioctl is only meant to enhance (and not replace) normal access
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* to the mmc bus device, an upper data transfer limit of MMC_IOC_MAX_BYTES
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* is enforced per ioctl call. For larger data transfers, use the normal
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* block device operations.
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*/
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#define MMC_IOC_MAX_BYTES (512L * 1024)
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#define MMC_IOC_MAX_CMDS 255
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#endif /* LINUX_MMC_IOCTL_H */
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