Alexei Starovoitov
cf2d0a5e78
Merge branch 'allow variable-offset stack acces'
Andrei Matei says: ==================== Before this patch, variable offset access to the stack was dissalowed for regular instructions, but was allowed for "indirect" accesses (i.e. helpers). This patch removes the restriction, allowing reading and writing to the stack through stack pointers with variable offsets. This makes stack-allocated buffers more usable in programs, and brings stack pointers closer to other types of pointers. The motivation is being able to use stack-allocated buffers for data manipulation. When the stack size limit is sufficient, allocating buffers on the stack is simpler than per-cpu arrays, or other alternatives. V2 -> V3 - var-offset writes mark all the stack slots in range as initialized, so that future reads are not rejected. - rewrote the C test to not use uprobes, as per Andrii's suggestion. - addressed other review comments from Alexei. V1 -> V2 - add support for var-offset stack writes, in addition to reads - add a C test - made variable offset direct reads no longer destroy spilled registers in the access range - address review nits ==================== Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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