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[kernel] Stop creating user stacks in the kernel

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Stop creating stacks in user space for user threads, that should be done
by the thread's creator. This change adds process and stack_top
arguments to the thread_create syscall, so that threads can be created
in other processes, and given a stack address.

Also included is a fix in add_thunk_user due to the r11/flags change.

THIS COMMIT BREAKS USERSPACE. See subsequent commits for the user side
changes related to this change.
This commit is contained in:
Justin C. Miller
2021-12-26 15:36:59 -08:00
parent cade24a7ce
commit 300bf9c2c5
6 changed files with 24 additions and 27 deletions
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13
src/kernel/objects/thread.cpp
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@@ -172,14 +172,15 @@ thread::add_thunk_user(uintptr_t rip3, uintptr_t rip0, uint64_t flags)
// b) come out of the kernel/user trampoline and start executing
// in user mode at rip
m_tcb.rsp -= sizeof(uintptr_t) * 8;
uintptr_t *stack = reinterpret_cast<uintptr_t*>(m_tcb.rsp);
flags |= 0x200;
m_tcb.rflags3 = flags;
stack[7] = rip3; // return rip in rcx
stack[6] = m_tcb.rsp3; // rbp
stack[5] = 0xbbbbbbbb; // rbx
stack[4] = flags; // r11 sets RFLAGS
m_tcb.rsp -= sizeof(uintptr_t) * 7;
uintptr_t *stack = reinterpret_cast<uintptr_t*>(m_tcb.rsp);
stack[6] = rip3; // return rip in rcx
stack[5] = m_tcb.rsp3; // rbp
stack[4] = 0xbbbbbbbb; // rbx
stack[3] = 0x12121212; // r12
stack[2] = 0x13131313; // r13
stack[1] = 0x14141414; // r14