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2023-04-20um: make stub data pages size tweakableJohannes Berg1-1/+1
There's a lot of code here that hard-codes that the data is a single page, and right now that seems to be sufficient, but to make it easier to change this in the future, add a new STUB_DATA_PAGES constant and use it throughout the code. Signed-off-by: Johannes Berg <[email protected]> Signed-off-by: Richard Weinberger <[email protected]>
2021-08-26um: fix stub location calculationJohannes Berg1-2/+1
In commit 9f0b4807a44f ("um: rework userspace stubs to not hard-code stub location") I changed stub_segv_handler() to do a calculation with a pointer to a stack variable to find the data page that we're using for the stack and the rest of the data. This same commit was meant to do it as well for stub_clone_handler(), but the change inadvertently went into commit 84b2789d6115 ("um: separate child and parent errors in clone stub") instead. This was reported to not be compiled correctly by gcc 5, causing the code to crash here. I'm not sure why, perhaps it's UB because the var isn't initialized? In any case, this trick always seemed bad, so just create a new inline function that does the calculation in assembly. Reported-by: [email protected] Fixes: 9f0b4807a44f ("um: rework userspace stubs to not hard-code stub location") Fixes: 84b2789d6115 ("um: separate child and parent errors in clone stub") Signed-off-by: Johannes Berg <[email protected]> Signed-off-by: Richard Weinberger <[email protected]>
2021-02-12um: rework userspace stubs to not hard-code stub locationJohannes Berg1-2/+3
The userspace stacks mostly have a stack (and in the case of the syscall stub we can just set their stack pointer) that points to the location of the stub data page already. Rework the stubs to use the stack pointer to derive the start of the data page, rather than requiring it to be hard-coded. In the clone stub, also integrate the int3 into the stack remap, since we really must not use the stack while we remap it. This prepares for putting the stub at a variable location that's not part of the normal address space of the userspace processes running inside the UML machine. Signed-off-by: Johannes Berg <[email protected]> Signed-off-by: Richard Weinberger <[email protected]>
2020-10-26arch/um: partially revert the conversion to __section() macroLinus Torvalds1-1/+1
A couple of um files ended up not including the header file that defines the __section() macro, and the simplest fix is to just revert the change for those files. Fixes: 33def8498fdd treewide: Convert macro and uses of __section(foo) to __section("foo") Reported-and-tested-by: Guenter Roeck <[email protected]> Cc: Joe Perches <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2020-10-25treewide: Convert macro and uses of __section(foo) to __section("foo")Joe Perches1-1/+1
Use a more generic form for __section that requires quotes to avoid complications with clang and gcc differences. Remove the quote operator # from compiler_attributes.h __section macro. Convert all unquoted __section(foo) uses to quoted __section("foo"). Also convert __attribute__((section("foo"))) uses to __section("foo") even if the __attribute__ has multiple list entry forms. Conversion done using the script at: https://lore.kernel.org/lkml/[email protected]/2-convert_section.pl Signed-off-by: Joe Perches <[email protected]> Reviewed-by: Nick Desaulniers <[email protected]> Reviewed-by: Miguel Ojeda <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2018-03-29um: Compile with modern headersJason A. Donenfeld1-0/+1
Recent libcs have gotten a bit more strict, so we actually need to include the right headers and use the right types. This enables UML to compile again. Signed-off-by: Jason A. Donenfeld <[email protected]> Cc: [email protected] Signed-off-by: Richard Weinberger <[email protected]>
2018-02-19um: Use POSIX ucontext_t instead of struct ucontextKrzysztof Mazur1-1/+1
glibc 2.26 removed the 'struct ucontext' to "improve" POSIX compliance and break programs, including User Mode Linux. Fix User Mode Linux by using POSIX ucontext_t. This fixes: arch/um/os-Linux/signal.c: In function 'hard_handler': arch/um/os-Linux/signal.c:163:22: error: dereferencing pointer to incomplete type 'struct ucontext' mcontext_t *mc = &uc->uc_mcontext; arch/x86/um/stub_segv.c: In function 'stub_segv_handler': arch/x86/um/stub_segv.c:16:13: error: dereferencing pointer to incomplete type 'struct ucontext' &uc->uc_mcontext); Cc: [email protected] Signed-off-by: Krzysztof Mazur <[email protected]> Signed-off-by: Richard Weinberger <[email protected]>
2012-10-09um: get rid of pointless include "..." where include <...> will doAl Viro1-3/+3
Signed-off-by: Al Viro <[email protected]> Signed-off-by: Richard Weinberger <[email protected]>
2011-11-02um: take arch/um/sys-x86 to arch/x86/umAl Viro1-0/+19
Signed-off-by: Al Viro <[email protected]> Signed-off-by: Richard Weinberger <[email protected]>