unimore/kernel-hacking-2024-linux-steffo
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um: add mmap/mremap OS calls

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For the upcoming shared-memory time-travel external
optimisations, we need to be able to mmap/mremap.
Add the necessary OS calls.

Link: https://patch.msgid.link/20240702192118.ca4472963638.Ic2da1d3a983fe57340c1b693badfa9c5bd2d8c61@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Johannes Berg 2024-07-02 19:21:20 +02:00
parent 5cde6096a4
commit e20f9b3c59
2 changed files with 25 additions and 0 deletions
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2
arch/um/include/shared/os.h
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@ -181,6 +181,8 @@ extern int os_eventfd(unsigned int initval, int flags);
extern int os_sendmsg_fds(int fd, const void *buf, unsigned int len,
const int *fds, unsigned int fds_num);
int os_poll(unsigned int n, const int *fds);
void *os_mmap_rw_shared(int fd, size_t size);
void *os_mremap_rw_shared(void *old_addr, size_t old_size, size_t new_size);
/* start_up.c */
extern void os_early_checks(void);

23
arch/um/os-Linux/file.c
View file

@ -17,6 +17,7 @@
#include <sys/stat.h>
#include <sys/sysmacros.h>
#include <sys/un.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/eventfd.h>
#include <poll.h>
@ -718,3 +719,25 @@ int os_poll(unsigned int n, const int *fds)
return -EIO;
}
void *os_mmap_rw_shared(int fd, size_t size)
{
void *res = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (res == MAP_FAILED)
return NULL;
return res;
}
void *os_mremap_rw_shared(void *old_addr, size_t old_size, size_t new_size)
{
void *res;
res = mremap(old_addr, old_size, new_size, MREMAP_MAYMOVE, NULL);
if (res == MAP_FAILED)
return NULL;
return res;
}