143 lines
3.5 KiB
C
143 lines
3.5 KiB
C
#include <zinnia/compiler.h>
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#include <zinnia/percpu.h>
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#include <arch/usercopy.h>
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#include <x86_64/percpu.h>
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void arch_usercopy_allow(bool state) {
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if (!percpu_ref(arch_data)->can_smap)
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return;
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if (state) {
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asm volatile("stac" ::: "memory");
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} else {
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asm volatile("clac" ::: "memory");
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}
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}
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extern void x86_64_read_start();
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extern void x86_64_read_end();
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extern void x86_64_read_fault();
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static const struct usercopy_region read_region = {
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.start_ip = x86_64_read_start,
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.end_ip = x86_64_read_end,
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.fault_ip = x86_64_read_fault,
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};
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[[__naked]]
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bool arch_usercopy_read(void* dst, const __user void* src, size_t len, struct usercopy_region** region) {
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asm volatile(
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// Setup regs for `rep movsb`.
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" xchg rcx, rdx\n"
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" lea rax, [rip + %0]\n"
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" xchg [rdx], rax\n"
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".global x86_64_read_start\n"
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" x86_64_read_start:\n"
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" rep movsb\n"
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".global x86_64_read_end\n"
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"x86_64_read_end:\n"
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" xor rax, rax\n"
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" xchg [rdx], rax\n"
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" mov rax, 1\n"
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" ret\n"
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".global x86_64_read_fault\n"
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"x86_64_read_fault:\n"
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" xor rax, rax\n"
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" mov [rdx], rax\n"
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" ret\n"
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:
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: "i"(&read_region)
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: "memory"
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);
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}
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extern void x86_64_write_start();
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extern void x86_64_write_end();
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extern void x86_64_write_fault();
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static const struct usercopy_region write_region = {
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.start_ip = x86_64_write_start,
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.end_ip = x86_64_write_end,
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.fault_ip = x86_64_write_fault,
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};
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[[__naked]]
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bool arch_usercopy_write(__user void* dst, const void* src, size_t len, struct usercopy_region** region) {
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asm volatile(
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// Setup regs for `rep movsb`.
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" xchg rcx, rdx\n"
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" lea rax, [rip + %0]\n"
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" mov [rdx], rax\n"
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".global x86_64_write_start\n"
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" x86_64_write_start:\n"
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" rep movsb\n"
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".global x86_64_write_end\n"
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" x86_64_write_end:\n"
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" xor rax, rax\n"
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" xchg [rdx], rax\n"
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" mov rax, 1\n"
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" ret\n"
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".global x86_64_write_fault\n"
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"x86_64_write_fault:\n"
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" xor rax, rax\n"
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" mov [rdx], rax\n"
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" ret\n"
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:
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: "i"(&write_region)
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: "memory"
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);
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}
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extern void x86_64_strlen_start();
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extern void x86_64_strlen_end();
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extern void x86_64_strlen_fault();
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static const struct usercopy_region strlen_region = {
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.start_ip = x86_64_strlen_start,
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.end_ip = x86_64_strlen_end,
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.fault_ip = x86_64_strlen_fault,
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};
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[[__naked]]
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bool arch_usercopy_strlen(const __user char* str, size_t max, size_t* len, struct usercopy_region** region) {
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asm volatile(
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" lea rax, [rip + %0]\n"
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" xchg [rcx], rax\n"
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".global x86_64_strlen_start\n"
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" x86_64_strlen_start:\n"
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" xor r8, r8\n"
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".Lloop:\n"
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" cmp r8, rsi\n"
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" je .Lleave\n"
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" cmp byte ptr [rdi + r8], 0\n"
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" je .Lleave\n"
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" inc r8\n"
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" jmp .Lloop\n"
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".Lleave:\n"
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" mov [rdx], r8\n"
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".global x86_64_strlen_end\n"
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"x86_64_strlen_end:\n"
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" xor rax, rax\n"
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" xchg [rcx], rax\n"
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" mov rax, 1\n"
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" ret\n"
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".global x86_64_strlen_fault\n"
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"x86_64_strlen_fault:\n"
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" xor rax, rax\n"
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" mov [rcx], rax\n"
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" ret\n"
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:
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: "i"(&strlen_region)
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: "memory"
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);
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}
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