a1c965da1e
Sixty-five headers sat side by side in include/, so `#include "irq.h"` said nothing about where irq.h was or what it belonged to, and errno.h, stat.h and fcntl.h at the top shadowed the system's for any host tool built with -I./include. They are in folders now -- arch/ core/ fs/ dev/ gfx/ net/ uapi/ (and ldls/ for the Linux driver layer) -- and every include names the folder, as Linux's do: "core/proc.h". Done mechanically and checked the hard way: the kernel built from this tree disassembles identically to the one built from the tree before it. The full image boots, and userland is the same set of programs. Paths in docs and comments follow; docs/guides/layout.md has a table of what is where, and tools/fix-includes.py rewrites old-style includes from the folders in the tree, for code written before this. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01S1giNvrHTrPMPw7V6x1kQ4
132 lines
3.1 KiB
C
132 lines
3.1 KiB
C
#include "core/types.h"
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#include "core/defs.h"
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#include "core/param.h"
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#include "arch/x86.h"
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#include "arch/memlayout.h"
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#include "arch/mmu.h"
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#include "core/proc.h"
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#include "core/spinlock.h"
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void
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initlock(struct spinlock *lk, char *name)
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{
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lk->name = name;
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lk->locked = 0;
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lk->cpu = 0;
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}
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void
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acquire(struct spinlock *lk)
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{
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pushcli();
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if(holding(lk))
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panic("acquire");
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{
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uint64 spins = 0;
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while(xchg(&lk->locked, 1) != 0){
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if(++spins == 200000000ULL){
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cprintf("acquire: stuck on \"%s\" held by cpu=%p pcs0=%p pcs1=%p pcs2=%p, acquirer cpu=%p\n",
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lk->name, lk->cpu, lk->pcs[0], lk->pcs[1], lk->pcs[2], mycpu());
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panic("acquire: deadlock");
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}
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}
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}
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__sync_synchronize();
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lk->cpu = mycpu();
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getcallerpcs(&lk, lk->pcs);
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}
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void
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release(struct spinlock *lk)
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{
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if(!holding(lk))
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panic("release");
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lk->pcs[0] = 0;
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lk->cpu = 0;
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__sync_synchronize();
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asm volatile("movq $0, %0" : "+m" (lk->locked) : );
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popcli();
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}
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void
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getcallerpcs(void *v, addr_t pcs[])
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{
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addr_t *rbp;
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asm volatile("mov %%rbp, %0" : "=r" (rbp));
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getstackpcs(rbp, pcs);
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}
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void
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getstackpcs(addr_t *rbp, addr_t pcs[])
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{
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int i;
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for(i = 0; i < 10; i++){
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// This walks a frame chain that may be garbage -- it runs from
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// getcallerpcs() on every lock acquisition, and again from the trap
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// handler, where the thing being diagnosed is often the reason the stack
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// is unwalkable. A fault here replaces the real diagnosis with a second,
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// more confusing one, so every dereference is checked first.
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//
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// The old test also compared against 0xffffffff, which on x86-64 is
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// unreachable: it is far below KERNBASE and the check above already
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// rejected it. The value that actually turns up is all-ones,
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// 0xffffffffffffffff, which is *above* KERNBASE and sailed straight
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// through -- rbp[1] then wraps to address 0x7 and page-faults. Bound rbp
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// from above rather than naming another magic constant, so any frame
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// pointer near the top of the address space is rejected whatever it is.
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if(rbp == 0 || rbp < (addr_t*)KERNBASE || (addr_t)rbp > (addr_t)-16)
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break;
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// A frame pointer is 8-byte aligned. An unaligned one is not a frame,
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// and following it walks off into arbitrary memory.
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if(((addr_t)rbp & 7) != 0)
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break;
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pcs[i] = rbp[1];
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rbp = (addr_t*)rbp[0];
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}
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for(; i < 10; i++)
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pcs[i] = 0;
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}
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int
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holding(struct spinlock *lock)
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{
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return lock->locked && lock->cpu == mycpu();
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}
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void
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pushcli(void)
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{
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int eflags;
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eflags = readeflags();
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cli();
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if(mycpu() == 0){
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extern uint64 kernel_fs_base;
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cprintf("pushcli: cpu==NULL cs=0x%p kernel_fs_base=0x%p actual_fs_base=0x%p\n",
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readcs(), kernel_fs_base, rdmsr(0xC0000100));
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panic("pushcli: cpu is NULL");
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}
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if(mycpu()->ncli == 0)
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mycpu()->intena = eflags & FL_IF;
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mycpu()->ncli += 1;
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}
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void
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popcli(void)
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{
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if(readeflags()&FL_IF)
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panic("popcli - interruptible");
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if(--mycpu()->ncli < 0)
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panic("popcli");
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if(mycpu()->ncli == 0 && mycpu()->intena)
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sti();
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}
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