Clean up; cpuid is always supported on x86_64 & RSP/SS always pushed (thanks Octocontrabass)

Author: maxdev1

kernel/src/kernel/system/processor/processor.asm

@@ -21,32 +21,8 @@
 
 BITS 64
 
-global _checkForCPUID
 global _enableSSE
 
-;
-; bool checkForCPUID()
-;
-; Checks if the CPUID instruction is available. This is implemented in
-; pure assembly, because C/C++ could cause race conditions due to the
-; ability of the compiler to modify the RFLAGS when it needs to.
-;
-_checkForCPUID:
-    pushfq
-    pop rax
-    mov rcx, rax
-    xor rax, 0x200000
-    push rax
-    popfq
-    pushfq
-    pop rax
-    xor rax, rcx
-    shr rax, 21
-    and rax, 1
-    push rcx
-    popfq
-    ret
-
 ;
 ; void enableSSE()
 ;

kernel/src/kernel/system/processor/processor.cpp

@@ -47,9 +47,6 @@ g_processor* _processorGetCurrent()
 
 void processorInitializeBsp()
 {
-	if(!processorSupportsCpuid())
-		panic("%! processor has no CPUID support", "cpu");
-
 	processorPrintInformation();
 
 	if(!processorHasFeature(g_cpuid_standard_edx_feature::APIC))
@@ -182,11 +179,6 @@ bool processorListAvailable()
 	return processors != nullptr;
 }
 
-bool processorSupportsCpuid()
-{
-	return _checkForCPUID();
-}
-
 void processorCpuid(uint32_t code, uint32_t* outA, uint32_t* outB, uint32_t* outC, uint32_t* outD)
 {
 	asm volatile("cpuid"

kernel/src/kernel/system/processor/processor.hpp

@@ -120,16 +120,6 @@ struct g_processor
     g_processor* next;
 };
 
-/**
- * Checks whether the CPU supports the CPUID instruction.
- */
-extern "C" bool _checkForCPUID();
-
-/**
- * Checks if the processor supports CPUID.
- */
-bool processorSupportsCpuid();
-
 /**
  * Performs a CPUID call and returns values in the out parameters.
  */

kernel/src/kernel/system/processor/processor_state.hpp

@@ -58,7 +58,6 @@ struct g_processor_state
 	uint64_t cs;
 	uint64_t rflags;
 
-	// Only pushed/popped on Ring 3 <-> Ring 0 switches
 	uint64_t rsp;
 	uint64_t ss;
 }__attribute__((packed));