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um: compress memory related stub syscalls while adding them

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To keep the number of syscalls that the stub has to do lower, compress
two consecutive syscalls of the same type if the second is just a
continuation of the first.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20240703134536.1161108-6-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Benjamin Berg 2024-07-03 15:45:29 +02:00 committed by Johannes Berg
parent 76ed9158e1
commit 6d8992e49e
1 changed files with 39 additions and 0 deletions
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39
arch/um/os-Linux/skas/mem.c
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@ -151,12 +151,37 @@ struct stub_syscall *syscall_stub_alloc(struct mm_id *mm_idp)
return sc;
}
static struct stub_syscall *syscall_stub_get_previous(struct mm_id *mm_idp,
int syscall_type,
unsigned long virt)
{
if (mm_idp->syscall_data_len > 0) {
struct stub_data *proc_data = (void *) mm_idp->stack;
struct stub_syscall *sc;
sc = &proc_data->syscall_data[mm_idp->syscall_data_len - 1];
if (sc->syscall == syscall_type &&
sc->mem.addr + sc->mem.length == virt)
return sc;
}
return NULL;
}
void map(struct mm_id *mm_idp, unsigned long virt, unsigned long len, int prot,
int phys_fd, unsigned long long offset)
{
struct stub_syscall *sc;
/* Compress with previous syscall if that is possible */
sc = syscall_stub_get_previous(mm_idp, STUB_SYSCALL_MMAP, virt);
if (sc && sc->mem.prot == prot && sc->mem.fd == phys_fd &&
sc->mem.offset == MMAP_OFFSET(offset - sc->mem.length)) {
sc->mem.length += len;
return;
}
sc = syscall_stub_alloc(mm_idp);
sc->syscall = STUB_SYSCALL_MMAP;
sc->mem.addr = virt;
@ -170,6 +195,13 @@ void unmap(struct mm_id *mm_idp, unsigned long addr, unsigned long len)
{
struct stub_syscall *sc;
/* Compress with previous syscall if that is possible */
sc = syscall_stub_get_previous(mm_idp, STUB_SYSCALL_MUNMAP, addr);
if (sc) {
sc->mem.length += len;
return;
}
sc = syscall_stub_alloc(mm_idp);
sc->syscall = STUB_SYSCALL_MUNMAP;
sc->mem.addr = addr;
@ -181,6 +213,13 @@ void protect(struct mm_id *mm_idp, unsigned long addr, unsigned long len,
{
struct stub_syscall *sc;
/* Compress with previous syscall if that is possible */
sc = syscall_stub_get_previous(mm_idp, STUB_SYSCALL_MPROTECT, addr);
if (sc && sc->mem.prot == prot) {
sc->mem.length += len;
return;
}
sc = syscall_stub_alloc(mm_idp);
sc->syscall = STUB_SYSCALL_MPROTECT;
sc->mem.addr = addr;