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Kernel: Allow Processor compilation for i386 targets 

This is achieved by rewriting some inline assembly and changing
ProcessorID to be 32 bit value. For some reason if processor id
is 8 bits gcc runs out of 8 bit registers on i386.
This commit is contained in:
Bananymous 2024-03-22 13:33:13 +02:00
parent 0424082e7b
commit 7f029b2713
2 changed files with 19 additions and 18 deletions
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26
kernel/include/kernel/Processor.h
View File

@ -16,10 +16,10 @@ namespace Kernel
Enabled,
};
using ProcessorID = uint8_t;
constexpr ProcessorID PROCESSOR_NONE = 0xFF;
using ProcessorID = uint32_t;
constexpr ProcessorID PROCESSOR_NONE = 0xFFFFFFFF;
#if ARCH(x86_64)
#if ARCH(x86_64) || ARCH(i386)
class Processor
{
BAN_NON_COPYABLE(Processor);
@ -75,16 +75,16 @@ namespace Kernel
template<typename T>
static T read_gs_sized(uintptr_t offset) requires(sizeof(T) <= 8)
{
#define __ASM_INPUT(operation) operation " %%gs:%a[offset], %[result]" : [result]"=r"(result) : [offset]"ir"(offset)
#define __ASM_INPUT(operation) asm volatile(operation " %%gs:%a[offset], %[result]" : [result]"=r"(result) : [offset]"ir"(offset))
T result;
if constexpr(sizeof(T) == 8)
asm volatile(__ASM_INPUT("movq"));
__ASM_INPUT("movq");
if constexpr(sizeof(T) == 4)
asm volatile(__ASM_INPUT("movl"));
__ASM_INPUT("movl");
if constexpr(sizeof(T) == 2)
asm volatile(__ASM_INPUT("movw"));
__ASM_INPUT("movw");
if constexpr(sizeof(T) == 1)
asm volatile(__ASM_INPUT("movb"));
__ASM_INPUT("movb");
return result;
#undef __ASM_INPUT
}
@ -92,15 +92,15 @@ namespace Kernel
template<typename T>
static void write_gs_sized(uintptr_t offset, T value) requires(sizeof(T) <= 8)
{
#define __ASM_INPUT(operation) operation " %[value], %%gs:%a[offset]" :: [value]"r"(value), [offset]"ir"(offset) : "memory"
#define __ASM_INPUT(operation) asm volatile(operation " %[value], %%gs:%a[offset]" :: [value]"r"(value), [offset]"ir"(offset) : "memory")
if constexpr(sizeof(T) == 8)
asm volatile(__ASM_INPUT("movq"));
__ASM_INPUT("movq");
if constexpr(sizeof(T) == 4)
asm volatile(__ASM_INPUT("movl"));
__ASM_INPUT("movl");
if constexpr(sizeof(T) == 2)
asm volatile(__ASM_INPUT("movw"));
__ASM_INPUT("movw");
if constexpr(sizeof(T) == 1)
asm volatile(__ASM_INPUT("movb"));
__ASM_INPUT("movb");
#undef __ASM_INPUT
}

11
kernel/kernel/Processor.cpp
View File

@ -13,14 +13,13 @@ namespace Kernel
static ProcessorID read_processor_id()
{
uint8_t id;
uint32_t id;
asm volatile(
"movl $1, %%eax;"
"cpuid;"
"shrl $24, %%ebx;"
"movb %%bl, %0;"
: "=rm"(id)
:: "eax", "ebx", "ecx", "edx"
: "=b"(id)
:: "eax", "ecx", "edx"
);
return id;
}
@ -55,7 +54,9 @@ namespace Kernel
// set gs base to pointer to this processor
uint64_t ptr = reinterpret_cast<uint64_t>(&processor);
asm volatile("wrmsr" :: "d"(ptr >> 32), "a"(ptr), "c"(MSR_IA32_GS_BASE));
uint32_t ptr_hi = ptr >> 32;
uint32_t ptr_lo = ptr & 0xFFFFFFFF;
asm volatile("wrmsr" :: "d"(ptr_hi), "a"(ptr_lo), "c"(MSR_IA32_GS_BASE));
ASSERT(processor.m_gdt);
processor.gdt().load();